feat: allow to do git commits with a custom user

[gabor-boros]

Description

This PR allows Picasso's users to set a custom user and email for the git commit step. The default values of the new inputs are the same as it was assigned earlier, therefore not setting the values result in the same GitHub user and email address as it was before this PR.

[gabor-boros]

Hey @magajh may I ask for a review on this? 😊

[MaferMazu]

This looks good to me.

@magajh, do you have something to add?

[magajh]

LGTM as well, although I haven't had a chance to test it yet. @MaferMazu, did you get a chance to test it?

[magajh]

Hey @gabor-boros, I just pushed the fix for the RTD check. Could you please rebase your branch onto main?

[MaferMazu]

LGTM as well, although I haven't had a chance to test it yet. @MaferMazu, did you get a chance to test it?

@magajh, I haven't tested execution directly since these inputs are optional and don't break existing behavior.

However, @gabor-boros, I ran a quick check through Gemini, and it flagged a potential shell injection risk with direct ${{ inputs.* }} interpolation.

Recommendation:

        env:
          GIT_COMMIT_USER_NAME: ${{ inputs.GIT_COMMIT_USER_NAME }}
          GIT_COMMIT_USER_EMAIL: ${{ inputs.GIT_COMMIT_USER_EMAIL }}
        run: |
          git config user.name "$GIT_COMMIT_USER_NAME"
          git config user.email "$GIT_COMMIT_USER_EMAIL"

Extra ref: https://docs.github.com/en/actions/reference/security/secure-use#use-an-intermediate-environment-variable