Add auto labeler workflow

[ohltyler]

Signed-off-by: Tyler Ohlsen ohltyler@amazon.com

Description

This PR adds a labeling github action which is triggered on PRs opening to main. There are 2 added files:

1. .github/labeler.yml: configures the labels to add to the PR, if the PR's changed files match any of the glob patterns specified. For example, this adds a dependencies label whenever a PR is opened that changes yarn.lock.
2. .github/workflows/labeler.yml: the actual github action which uses the specified config. Uses permissions from the OpenSearch GitHub app to be able to write to the PR, since that is not possible using the default GITHUB_TOKEN. For more details see here, here

Example PR of this working in my forked repo (using a personal bot in order to get permissions to write to PRs in this repo): ohltyler#7 (auto-label workflow run: link)

Notes:

• it is defaulting all changes to backport 1.x - this is because this plugin is not tracking the next major version (2.0.0), and so all changes merged to main currently are being backported to 1.x branch already (note this will need to change when moving to 2.0.0 compatibility / having 2.x branch). Also note backport 1.x is the branch name used by the auto-backport bot to open a backport PR to 1.x branch when a PR is merged, so this closes the gap and allows for a fully automated way to open a PR -> merge PR -> backport to release branch.
• it will add or remove labels based on changes in the PR - for example if yarn.lock was originally changed and then reverted within the PR, the labeler would add and remove the dependencies label as well
• .github/**/* pattern had to be added separately in backport 1.x label due to the labeler not picking up directories starting with . by default

TODO: understand the github bot permissions and if it can be used for this github action. Until then, this PR is blocked when trying to use the default repo token. Ref: actions/first-interaction#10, use of an app to solve: mentioned here

Check List

• Commits are signed per the DCO using --signoff

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[codecov-commenter]

Codecov Report

Merging #205 (633ad07) into main (9ae8917) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #205   +/-   ##
=======================================
  Coverage   45.90%   45.90%           
=======================================
  Files         150      150           
  Lines        4956     4956           
  Branches      955      968   +13     
=======================================
  Hits         2275     2275           
  Misses       2463     2463           
  Partials      218      218           

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[ohltyler]

The backport 1.x label can be tuned in the near future to backport 2.x once main is bumped to 2.0 and a 2.x branch is cut.

[amitgalitz]

This is really helpful!