Dvc

* dvc: remove `dvc metrics add/remove` (3928) efiop
* refactor: rename utils.stage to utils.yaml (3923) skshetry
* Fix modifying plot (3926) Suor
* bugfix: rerun stage when command is changed (3922) skshetry
* dvc: replace `pipeline` with `dag` (3905) efiop
* Implement removing of the stage (3881) skshetry
* dvc: rename "working tree" to "workspace" (3914) efiop
* dvc: rename `dvc lock` -> `dvc freeze` (3915) efiop
* Add plots props and `plots modify` params (3911) Suor
* use fork of mockssh-server (3910) skshetry
* pre-commit: don't run dvc in parallel (3912) efiop
* use `selectors` instead of `select.select()` (3899) skshetry
* Update bug report template (3903) jorgeorpinel
* tests: make ssh_server session scoped (3898) efiop
* dvcignore: use correct root .dvcignore for subrepos (3895) pmrowla
* plots: replace --show-json with --show-vega (3891) efiop
* Bugfix: _credentials_location (3896) nickdelgrosso
* brancher: only yield git revisions that contain repo_root (3883) pmrowla
* modify issue template (3887) skshetry

* dvcignore: fix bug in subrepo detection (3880) efiop
* run: raise error when command is not specified (3850) skshetry
* ignore: CleanTree should always check ignores, not just for walk() (3876) pmrowla
* addressing: allow stage name addressing without ":" (3842) skshetry
* run-cache: don't forget to set wdir (3873) efiop
* state: always use working trees (3871) pmrowla
* log: reduce log, make it readable/easier (3834) skshetry

* optimize local status (3867) efiop
* Auto-completion of the `dvc remote rename` command (3868) karajan1001
* snap: release non-stable-semver tags to beta (3865) casperdcl
* test: fix hdfs/azurite/oss tests (3864) efiop
* tests: unit: azure: add etag test (3862) efiop
* azure: support external file dependencies (3852) steffansluis
* dvcfile: serialize params on --no-exec (3859) efiop

* remote: local: protect uploaded files (3858) pared
* azure: drop obsoleted url format (3856) efiop
* plot: fixup for template help message (3854) pared
* external_repo: use RepoTree for fetch/import/get (3841) pmrowla
* dvc: add: set top level md5 to None (3846) efiop
* params/metrics: introduce --no-path and --old (3845) efiop
* dvc: don't write default values for cache/persist/metric (3844) efiop
* plots: point template help info to manual (3830) pared
* run-cache: don't forget to account for params (3843) efiop
* plots: remove --select CLI option (3840) efiop
* (OutputAlreadyTrackedError): Add git suggestions to stop tracking files (3808) PuneethaPai
* remote: support saving RepoTree objects directly to cache (3825) pmrowla
* repro: fix help message for default target (3831) skshetry
* dvc : renamed --outs-only to --dvc-only (3797) growupboron
* logger: add trace, count --verbose/--quiet (3806) casperdcl

* remote: is_dir_checksum: handle empty/None checksum (3836) efiop
* Add a new rename command (3794) karajan1001
* lock: make froze message clickable (3833) pared

* plots: add plot markers to DVC files (3807) efiop
* Newline at the end of template files on init (3828) nik123
* default target: reduce loglevel to debug (3822) skshetry
* repro: do not log when stage is locked and is import (3823) skshetry
* plots: dont zero y axis (3813) pared
* utils: support use of (GitTree) tree file objects in utils (3819) pmrowla
* stage: fix commit (3816) efiop
* repo: Support streaming and pulling files on `RepoTree/DvcTree.open()` (3810) pmrowla
* pyupgrade: 3.6+ (3805) skshetry
* dvc.yaml: remove outs_no_cache, etc. keys, merge inside outs (3785) skshetry
* refactor: simplify checkouts and run, get rid of check_can_commit (3800) skshetry
* dvc: rename plot to plots (3802) efiop
* stage: fix --dry-run (3799) efiop
* stage: moving things around, refactor (3793) skshetry
* run/repro: rename "build cache" -> "run cache" (3788) efiop
* diff: handle repo with no commits (3784) efiop
* Drop Python 3.5 support (3792) pmrowla
* tests: mark test_data_cloud::test_pull_git_imports as flaky (3790) pmrowla
* plot: add doctype at the beggining of html embedding (3787) pared
* plot: update some output strings (3759) jorgeorpinel
* diff: autocompletion script for params, and show-md (3786) skshetry
* tests: abstract remote setup to fixture (3748) pared
* run-cache: support uncached files (3778) efiop
* Added S3 SSEKMSKeyId config option (3762) jackwellsxyz
* pipeline file: disallow punctuation characters in stage name (3767) skshetry
* refactor: check if targets is instances of str (3779) nik123
* import: check erepo is None before modifying url - fixes 3780 (3781) ned2
* params/metrics: diff: implement tabulated markdown output (--show-md) (3757) skshetry
* Import ABC from collections.abc for Python 3 compatibility. (3772) tirkarthi
* fix 3588 (3770) karajan1001
* Dvc remote default in list validation (3715) karajan1001
* push/pull: properly collect run cache (3768) efiop
* update: --recursive flag (3760) nik123
* stage: hide unwanted warnings (3763) efiop