Update on every build the git hash shown by rizin -v

[kazarmy]

Your checklist for this pull request

• I've read the guidelines for contributing to this repository
• I made sure to follow the project's coding style
• I've documented or updated the documentation of every function and struct this PR changes. If not so I've explained why.
• I've added tests that prove my fix is effective or that my feature works (if possible)
• I've updated the rizin book with the relevant information (if needed)

Detailed description

This pr updates on every build the git commit hash shown by rizin -v. Previously, the updating was done only on a meson configure, which doesn't happen on every commit and thus the git commit hash shown can sometimes be out-of-date.

Currently Python is used for the updating of the gittip file containing the commit hash. This shouldn't be too much of a burden though since Python is needed for meson and therefore should be in the cache.

Test plan

After this code is installed, add a new commit that doesn't cause build file regeneration. The commit hash shown by rizin -v should be the hash of the new commit. All builds are green.

Closing issues

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