Update the wishlist leaderboard script to handle PRs (paritytech#5256)

Addresses
paritytech#5085 (comment)

Luckily, in the rest of the script, github API allows (or forces?) us to
read the state of PRs the same way as we read the state of issues, so it
works without any more changes.

.github/scripts/update-wishlist-leaderboard.py

@@ -7,7 +7,7 @@
 
 # Regex pattern to match wish format:
 wish_pattern = re.compile(
-    r"I wish for:? (https://github\.com/([a-zA-Z0-9_.-]+)/([a-zA-Z0-9_.-]+)/issues/(\d+))"
+    r"I wish for:? (https://github\.com/([a-zA-Z0-9_.-]+)/([a-zA-Z0-9_.-]+)/(issues|pull)/(\d+))"
 )
 
 wishlist_issue = g.get_repo(os.getenv("WISHLIST_REPOSITORY")).get_issue(
@@ -28,7 +28,7 @@
 
     matches = wish_pattern.findall(updated_body)
     for match in matches:
-        url, org, repo_name, issue_id = match
+        url, org, repo_name, _, issue_id = match
         issue_key = (url, org, repo_name, issue_id)
         if issue_key not in wishes:
             wishes[issue_key] = []