Label merge strategy

[jetersen]

Prerequisites:

N/A

New Feature

At the moment labels are enforced at this moment.
I would like to have the option to only add/update labels and do not remove any labels that other github actions or developers want to use.
This properly means a merge strategy for labels. Overwrite vs Append

[dgroup]

The following labels will help us to estimate the pull request size:

GitHub label	Lines count
size/XS	1 - 10
size/S	11 - 30
size/M	31 - 100
size/L	101 - 500
size/XL	501 - 1000
size/XXL	1001+

The following GitHub action is used for estimation: https://github.com/kkohtaka/gh-actions-pr-size

[svg153]

@decyjphr Is the mixing strategy going to be implemented? In the version 2.0.21 (PR #408) include and exclude for labels have already been implemented. So, I think this issue could be closed.