handle-pr-comment: look for the PR in the correct repo

Signed-off-by: Johannes Schindelin <[email protected]>

Author: dscho

.github/workflows/handle-pr-comment.yml

@@ -56,9 +56,11 @@ jobs:
 
         PR_NUMBER="${PR_COMMENT_URL%#*}" # skip the suffix with the comment ID
         PR_NUMBER="${PR_NUMBER##*/}" # skip the prefix before the PR number
+        PR_REPO="${PR_COMMENT_URL%/$PR_NUMBER*#*}" # skip the suffix including the PR number
+        PR_REPO="${PR_REPO#https://.*/}"
 
         export GH_TOKEN="${{ secrets.GITHUB_TOKEN }}"
-        eval "$(gh api repos/gitgitgadget/git/pulls/$PR_NUMBER \
+        eval "$(gh api repos/$PR_REPO/pulls/$PR_NUMBER \
           --jq '"head_sha=\(.head.sha) && repo=\(.base.repo.full_name)"')"
         echo "head_sha=$head_sha" >> $GITHUB_OUTPUT
         echo "repo=$repo" >> $GITHUB_OUTPUT