Add a test for PRs that change README without updating the man page

[sparr]

Changes to README.rst require make man to update the man page in git-secrets.1. We should have a github action check that fails if a PR modifies one but not the other.

[peterklein2024]

name: Check Man Page Update
on:
pull_request:
paths: [README.rst, 'man/git-secrets.1']
jobs:
check-man-page:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v2
- uses: actions/setup-python@v2; with: python-version: '3.x'
- run: pip install -r requirements.txt; diff=$(git diff --name-only ${{ github.event.before }} ${{ github.sha }} | grep -E 'README.rst|man/git-secrets.1' || true); [ -n "$diff" ] && { echo "Error: Changes to README.rst or man/git-secrets.1 require corresponding updates in the other file."; exit 1; }
did this with my site hope it helps u