testsuite.yml - fix git breakage from fix for CVE-2022-24765

We need to configure git to know that our working directory is "safe".

This fixes this bug on github:

    Run git remote set-url origin "***[github.com/$GITHUB_REPOSITORY](http://github.com/$GITHUB_REPOSITORY)"
    fatal: unsafe repository ('/__w/perl5/perl5' is owned by someone else)
    To add an exception for this directory, call:

    git config --global --add safe.directory /__w/perl5/perl5
    Process completed with exit code 128.

See the git mailing list for more details on this CVE.

.github/workflows/testsuite.yml

@@ -211,7 +211,9 @@ jobs:
       # actions/checkout@v2 doesn't work in a container, so we use v1.
       - uses: actions/checkout@v1
       - name: fix git remote credential
-        run: git remote set-url origin "https://$GITHUB_ACTOR:${{ secrets.GITHUB_TOKEN }}@github.com/$GITHUB_REPOSITORY"
+        run: |
+          git config --global --add safe.directory /__w/perl5/perl5
+          git remote set-url origin "https://$GITHUB_ACTOR:${{ secrets.GITHUB_TOKEN }}@github.com/$GITHUB_REPOSITORY"
       - name: git cfg + fetch tags
         run: |
           git config diff.renameLimit 999999