PR scan - Check difference between best common ancestor

[attiasas]

• All tests passed. If this feature is not already covered by the tests, I added new tests.
• This pull request is on the dev branch.
• I used gofmt for formatting the code before submitting the pull request.
• Update documentation about new features / new supported technologies

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On Scan Pull Request command, we are preforming 2 scans.

1. On target branch
2. On source branch

After changes, we are now comparing the best common ancestor using git merge-base source target to determine the revision to compare the source against

[github-actions]

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🐸 JFrog Frogbot