.github: Fix the repatriation logic to deal with merged/closed PRs

If there's an old PR that's already been merged, that means we should be
creating a new one, rather than assuming that pushing to the branch will
update the old one.

As seen on https://github.com/emissary-ingress/emissary/runs/6523998225

Signed-off-by: Luke Shumaker <[email protected]>

.github/workflows/repatriate.yml

@@ -49,14 +49,15 @@ jobs:
             git push --set-upstream origin "$merge_branch"
           fi
 
-          if url=$(gh pr view --json=url --jq=.url); then
+          url=$(gh pr list --limit=1 --head="$merge_branch" --state=open --json=url --jq='.[0].url')
+          if [[ -n "$url" ]]; then
             echo "::set-output name=verb::Updated"
           else
             gh pr create \
               --title="[${next_ver}] Repatriate from ${this_ver}" \
               --body="This PR merges ${this_branch} in to ${next_branch}." \
               --base="$next_branch"
-            url=$(gh pr view --json=url --jq=.url)
+            url=$(gh pr list --limit=1 --head="$merge_branch" --state=open --json=url --jq='.[0].url')
             echo "::set-output name=verb::Created"
           fi
           echo "::set-output name=pr_url::${url}"