Cfn-lint

Features
- Created a new `mandatory-checks` parameter to require rules to be reported on and not ignored (pull [1243](https://github.com/aws-cloudformation/cfn-python-lint/pull/1243))
- Allow using modules when doing `append-rules` (pull [1216](https://github.com/aws-cloudformation/cfn-python-lint/pull/1216))
- Add support for the new zone `us-west-2-lax-1a` (pull [1241](https://github.com/aws-cloudformation/cfn-python-lint/pull/1241))
CloudFormation Specifications
- Update CloudFormation specs to 10.0.0 (pull [1247](https://github.com/aws-cloudformation/cfn-python-lint/pull/1247))
Fixes
- Update rule [E8001](https://github.com/aws-cloudformation/cfn-python-lint/blob/main/docs/rules.md#E8001) to allow for `Condition` (pull [1246](https://github.com/aws-cloudformation/cfn-python-lint/pull/1246))

CloudFormation Specifications
- Update pricing and services from 2019.12.02 (pull [1237](https://github.com/aws-cloudformation/cfn-python-lint/pull/1237))
- Update to specs to 9.1.1 (pull [1237](https://github.com/aws-cloudformation/cfn-python-lint/pull/1237))
Fixes
- `EnableVersionUpgrade` added to the recognized values for `UpdatePolicy` (pull [1231](https://github.com/aws-cloudformation/cfn-python-lint/pull/1231))
- Include `pathlib2` in python 3.4 requirements (pull [1236](https://github.com/aws-cloudformation/cfn-python-lint/pull/1236))
- Look at the top level Condition operator (pull [1235](https://github.com/aws-cloudformation/cfn-python-lint/pull/1235))
- Include more testing for using cfn-lint as a module (pull [1234](https://github.com/aws-cloudformation/cfn-python-lint/pull/1234))

CloudFormation Specifications
- Update CloudFormation specs to 9.1.0 (pull [1224](https://github.com/aws-cloudformation/cfn-python-lint/pull/1224))
- Add Allowed Pattern to Bucket Names (pull [1208](https://github.com/aws-cloudformation/cfn-python-lint/pull/1208))
Fixes
- Update rule [E2001](https://github.com/aws-cloudformation/cfn-python-lint/blob/main/docs/rules.md#E2001) to look for required properties (pull [1227](https://github.com/aws-cloudformation/cfn-python-lint/pull/1227))
- Update rule [E2503](https://github.com/aws-cloudformation/cfn-python-lint/blob/main/docs/rules.md#E2503) to allow `routing.http.drop_invalid_header_fields.enabled` for application load balancers (pull [1220](https://github.com/aws-cloudformation/cfn-python-lint/pull/1220))
- Update rule [E1028](https://github.com/aws-cloudformation/cfn-python-lint/blob/main/docs/rules.md#E1028) to check that Fn::If value is a list of length 3 (pull [1226](https://github.com/aws-cloudformation/cfn-python-lint/pull/1226))

CloudFormation Specifications
- Change DocDB allowed EngineVersion value to 3.6.0 (pull [1213](https://github.com/aws-cloudformation/cfn-python-lint/pull/1213))
Fixes
- Update rule [E3002](https://github.com/aws-cloudformation/cfn-python-lint/blob/main/docs/rules.md#E3002) to handle nested IFs when looking at lists (pull [1212](https://github.com/aws-cloudformation/cfn-python-lint/pull/1212))
- Update rule [W2501](https://github.com/aws-cloudformation/cfn-python-lint/blob/main/docs/rules.md#W2501) to only look at a Resource Properties (pull [1214](https://github.com/aws-cloudformation/cfn-python-lint/pull/1214))

CloudFormation Specifications
- Add capacityOptimized to spot fleet allocation strategy (pull [1200](https://github.com/aws-cloudformation/cfn-python-lint/pull/1200))
- Update Lambda runtime options to be valid as of 2019.11.19 (pull [1204](https://github.com/aws-cloudformation/cfn-python-lint/pull/1204))

CloudFormation Specifications
- Update allowed values for AWS Config types (pull [1197](https://github.com/aws-cloudformation/cfn-python-lint/pull/1197))
- Update CloudFormation specs to 8.1.0 (pull [1197](https://github.com/aws-cloudformation/cfn-python-lint/pull/1197))