Sceptre

Added
- [Resolve 1261] Add coloured differ (1260)
- Implements coloured diffs for the diff (difflib) command. Responds to --no-color.
- [Resolves 1271] Extend stack colourer to include "IMPORT" states (1272)
- [Resolves 1179] cloudformation disable-rollback option (1282)
- Allow user to disable a cloudformation rollback on a sceptre deployment.

Changed
- [Resolve 1098] Deploy docker container to sceptreorg repo (1265)
- Deploy sceptre docker images to dockerhub sceptreorg repo instead of cloudreach repo
- Updating Setuptools and wheel versions to avert security issues
- [Resolve 1293] Improve the Stack Config Jinja Syntax Error Message to include the Stack Name (1294)
- [Resolves 1267] Improve the Stack Config Jinja Error Message to include the Stack Name (1269)

Fixed
- [Resolve 1273] Events start from response time (1275)
- Resolves 1273 by starting event filtering from the timestamp returned in
the AWS response headers rather than relying on the workstation clock.
- [Resolve 1253] Failed downloads raise error (1277)
- Throwing an informative error when the template fails to download instead
of passing the error message to CloudFormation.
- [Resolves 1179] Changed disable-rollback default to None (1288)
- We want the default value to be None to represent "Do whatever's configured
in the StackConfig" and True/False will override the StackConfig.

Nonfunctional
- Add tweet-release to CircleCI config (1259)
- [Resolves 1276] Adopt Black Auto-formatter (1278)
- Reformatting all Python files using the Black code formatter. This also
delivers a new function for generating `__repr__` methods which was needed
to deal with a line-too-long issue in Template. Per discussion in 1276 this
PR also disables E203 in flake8.
- Update sceptre-circleci docker image (1284)
- Update to build and test with a docker image that's based on the official
circleci python docker image.
- [Resolve 1264] Updating the CDK docs to point to the new sceptre-cdk-handler
(1285)
- This updates our docs to no longer reference the old CDK approach (which
didn't work with CDK assets). In its place, it references the new
sceptre-cdk-handler package that covers that functionality.

Added
- [Resolve 1225] Added Python 3.10 support (1227)
- Implemented a `sceptre dump config` command (1220)
- [Resolve 1224] Add --drifted option to `drift show` command (1246)
- [Resolve 1212] Conditional Stacks via "ignore" and "obsolete";
`sceptre prune` command for cleaning up obsolete stacks (1229)

Changed
- [Resolve 1225] Updating `troposphere` version for python 3.10 compatibility (1226)
- [Resolve 1225] Updating Sceptre to use importlib on Python 3.10 (1240)

Fixed
- [Resolve 1218] Fixing false-diff reports when parameters end with linebreaks (1219)
- [Resolve 1236] Updating `networkx` to miticate CWE-502 (1243)
- [Resolve 1245] Updating `setuptools` version to address build failure (1247)
- [Resolve 1234] Bugfix to support empty var files (1248)
- [Resolve 1223] Fix crash when resolvers return lists of `None` (1249)

Nonfunctional
- Added sponsors section to CONTRIBUTING.md (1221)
- Made unit tests run in parallel when running `make test-all` (1231)
- Removing awscli from CircleCI builds (1232)
- Updated sceptre-circleci docker image for Python 3.10 support (1230)
- Using CircleCI cache to speed up builds (1242)

Added
- [Resolve 1080] Added duration_seconds parameter to adopt DurationSeconds in boto (1210)

Changed
- [Resolve 1203] Updating packaging requirement (1211)

Breaking Changes
- Python 3.6 support has been removed due to that version reaching end-of-life status
- Jinja2 has been upgraded to v3.0

Added
- [Resolve 1114,426] Resolvable stack_tags (1184)
- [Resolve 1114,886,491] Resolvable role_arn and template_bucket_name (1153)
- [Resolve 1114] Resolvable iam_role (1188)
- [Resolve 1114] Resolvable Template Handler configs and the !stack_attr resolver
- [Resolve 1167] Add list stacks command (1168)
- [Resolve 1169] Add drift detect and drift show commands (1170)

Removed
- [Resolves 1201] Remove Py3.6 support (1206)

Changed
- [Resolve 1114,1000] Placeholders for non-deployed stacks in non-deployment commands (1185)

Fixed
- [Resolves 1201] Fix dependency conflicts (Jinja2, moto) (1206)

Nonfunctional
- [Resolves 1194] Docs: "know"->"knows" (1195)
- docs: fix template path in getting-started (1198)
- Fix spelling of stack_group_config (1199)

Fixed

- [Resolve 1175] Adding commas for cfn-flip dependency (1176)
- [Partially resolves 1174] Fixing Docs deployment by pinning Sphinx to lesser version (1171)

Nonfunctional

- Fix typo in CDK doc (1181)
- Add release instructions (1162)
- Resolve 1163 update doc link to new domain (1166)
- Pointing SAM docs toward the sceptre-sam-handler (1164)

Added

- [Resolve 966] Add support for J2 Environment configuration
- [Resolves 919] Add merge_keys option (928)
- [Resolves 1064] Add feature list change-set --url (1065)
- [Resolves 213] Add support for template handlers (1088)
- [Resolves 1106] S3 template handler jinja and python support (1110)
- [Resolves 1124] http template handler (1125)
- Set file as the default template handler type (1127)
- Add retry and timeout to http template handler (1145)
- [Resolve 683] Introducing the Diff Command (1132)

Fixed

- [Resolves 813] Fix recursive config render (1083)
- [Resolve 1096] Gracefully executing SAM Change sets (1099)
- [Resolves 556] fix incorrect stack_output_external examples (1109)
- [RESOLVE 946] Fixing bug preventing StackGroup dependencies (1116)
- [Resolve 1138] Bugfix for j2_environments (1137)
- [Resolve 1135] Fix path to templates (1141)
- [Resolve 1143] fix "create" cmd with existing stack (1144)
- [Resolves 1148] Correct path logic (1149)

Nonfunctional

- [Resolves 582] update imp to importlib (1092)
- [Resolves 1090] Install troposphere as an extra package (1104)
- [Resolves 1087] Add YAML document markers to template body (1089)
- Stop hiding critical debug info in helpers (988) (997)
- [Resolves 1139] Provide useful info on invalid jinja file (1142)