ENG-1235: Push release tags automatically on rasa-sdk

[AsadHasan-Rasa]

Proposed changes:
Introduce mechanism to automatically create and push tag for release, similar to how it is already done in rasa-private. Summary of changes:

1. Updated scripts/release.py to create and push release tag, if invoked with --tag flag.
2. Updated Makefile with new target make tag-release.
3. Added GHA workflow tag-release, to do this in CI, when PR is merged to main or a release branch.

Status (please check what you already did):

• made PR ready for code review
• added some tests for the functionality
• Manually tested this locally, as described below*
• updated the documentation in the rasaHQ/rasa
• updated the changelog (please check changelog for instructions)
• Not required I think as this is internal-only change, and not user facing?
• reformat files using ruff (please check Readme for instructions)

*Ran make release and make tag-release locally, to see that a tag is created and pushed (Note: Tagging function checks that the branch is main or a final release branch (complying to regex pattern ^\d+\.\d+\.x$ for e.g. 1.2.x), so locally disabled this check so that I can test on a dev-test release branch):

(rasa-sdk-py3.10) asadhasan@ENG-UK-0011 ~/r/rasa-sdk (ENG-1235-push-release-tags-automatically-on-rasa-sdk) [1]> make release && make tag-release
poetry run python scripts/release.py
The release script will increase the version number, create a changelog and create a release branch. Let's go!
? What is the version number you want to release ('major', 'minor', 'micro', 'alpha', 'rc' or valid version number e.g. '3.10.1' or '3.10.1a1')? 3.10.0dev5
? Is the next version '3.10.0.dev5' correct (current version is '3.10.0.dev4')? Yes
Loading template...
Finding news fragments...
Rendering news fragments...
Writing to newsfile...
Staging newsfile...
No news fragments to remove. Skipping!
Done!
Switched to a new branch 'prepare-release-3.10.0.dev5'
[prepare-release-3.10.0.dev5 bda721c] prepared release of version 3.10.0.dev5
 6 files changed, 33 insertions(+), 7 deletions(-)
 delete mode 100644 changelog/1122.improvement.md
 delete mode 100644 changelog/1128.misc.md
 delete mode 100644 changelog/1135.misc.md
Enumerating objects: 13, done.
Counting objects: 100% (13/13), done.
Delta compression using up to 14 threads
Compressing objects: 100% (7/7), done.
Writing objects: 100% (7/7), 813 bytes | 813.00 KiB/s, done.
Total 7 (delta 6), reused 0 (delta 0), pack-reused 0
remote: Resolving deltas: 100% (6/6), completed with 6 local objects.
remote: 
remote: Create a pull request for 'prepare-release-3.10.0.dev5' on GitHub by visiting:
remote:      https://github.com/RasaHQ/rasa-sdk/pull/new/prepare-release-3.10.0.dev5
remote: 
remote: GitHub found 11 vulnerabilities on RasaHQ/rasa-sdk's default branch (1 high, 9 moderate, 1 low). To find out more, visit:
remote:      https://github.com/RasaHQ/rasa-sdk/security/dependabot
remote: 
To https://github.com/RasaHQ/rasa-sdk.git
 * [new branch]      HEAD -> prepare-release-3.10.0.dev5

 All done - changes for version 3.10.0.dev5 are ready! 

Please open a PR on GitHub: https://github.com/RasaHQ/rasa-sdk/compare/ENG-1235-push-release-tags-automatically-on-rasa-sdk...prepare-release-3.10.0.dev5?expand=1
poetry run python scripts/release.py --tag

    The release tag script will tag the current commit with the current version.

    This should be done on the applicable *.x branch after running
    `make release` and merging the prepared release branch.
        
Applying tag '3.10.0.dev5' to commit.
Pushing tag '3.10.0.dev5' to origin.
Enumerating objects: 2, done.
Counting objects: 100% (2/2), done.
Delta compression using up to 14 threads
Compressing objects: 100% (2/2), done.
Writing objects: 100% (2/2), 304 bytes | 304.00 KiB/s, done.
Total 2 (delta 0), reused 0 (delta 0), pack-reused 0
To https://github.com/RasaHQ/rasa-sdk.git
 * [new tag]         3.10.0.dev5 -> 3.10.0.dev5
 * [new tag]         3.10.0.dev2 -> 3.10.0.dev2

 All done - tag for version 3.10.0.dev5 was added and pushed to the remote 

[CLAassistant]

All committers have signed the CLA.

[sanchariGr]

Great job 🎉
Left two small comments and would be great if we could also test this before merge.
edit : I see you have tested this locally 🥇

[sanchariGr]

I think this PAT token doesnot exist for the repo. @rasa-aadlv can you help with this please?

[AsadHasan-Rasa]

RELEASE_TAGGER_PAT now added to this repo's secrets (thanks @rasa-aadlv !)

[sanchariGr]

Not related to your changes but just noticed this was missing. Can you also add and not version.dev here please? We shouldnt generate changelog for dev releases either.