Introduce a workflow updating the wishlist leaderboards (#5085)

- Closes paritytech/eng-automation#11

The workflow periodically updates the leaderboards of the wishlist
issues: #3900 and
#3901

The code is adopted from
[here](https://github.com/kianenigma/wishlist-tracker), with slight
modifications.

Previously, the score could be increased by the same person adding
different reactions. Also, some wishes have a score of 0 - even thought
there is a wish for them, because the author was not counted.

Now, the score is a unique count of upvoters of the desired issue,
upvoters of the wish comment, and the author of the wish comment.

I changed the format to include the `Last updated:` at the bottom - it
will be automatically updated.

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

@@ -0,0 +1,79 @@
+from github import Github
+import re
+import os
+from datetime import date
+
+g = Github(os.getenv("GH_TOKEN"))
+
+# 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+))"
+)
+
+wishlist_issue = g.get_repo(os.getenv("WISHLIST_REPOSITORY")).get_issue(
+    int(os.getenv("WISHLIST_ISSUE_NUMBER"))
+)
+new_leaderboard = (
+    "| Feature Request | Summary | Votes | Status |\n| --- | --- | --- | --- |\n"
+)
+wishes = {}
+issue_details = {}
+
+for comment in wishlist_issue.get_comments():
+    # in the comment body, if there is a string `#(\d)`, replace it with
+    # https://github.com/paritytech/polkadot-sdk/issues/(number)
+    updated_body = re.sub(
+        r"#(\d+)", r"https://github.com/paritytech/polkadot-sdk/issues/\1", comment.body
+    )
+
+    matches = wish_pattern.findall(updated_body)
+    for match in matches:
+        url, org, repo_name, issue_id = match
+        issue_key = (url, org, repo_name, issue_id)
+        if issue_key not in wishes:
+            wishes[issue_key] = []
+
+        # Get the author and upvoters of the wish comment.
+        wishes[issue_key].append(comment.user.id)
+        wishes[issue_key].extend(
+            [
+                reaction.user.id
+                for reaction in comment.get_reactions()
+                if reaction.content in ["+1", "heart", "rocket"]
+            ]
+        )
+
+        # Get upvoters of the desired issue.
+        desired_issue = g.get_repo(f"{org}/{repo_name}").get_issue(int(issue_id))
+        wishes[issue_key].extend(
+            [
+                reaction.user.id
+                for reaction in desired_issue.get_reactions()
+                if reaction.content in ["+1", "heart", "rocket"]
+            ]
+        )
+        issue_details[url] = [
+            desired_issue.title,
+            "👾 Open" if desired_issue.state == "open" else "✅Closed",
+        ]
+
+# Count unique wishes - the author of the wish, upvoters of the wish, and upvoters of the desired issue.
+for key in wishes:
+    wishes[key] = len(list(set(wishes[key])))
+
+# Sort wishes by count and add to the markdown table
+sorted_wishes = sorted(wishes.items(), key=lambda x: x[1], reverse=True)
+for (url, _, _, _), count in sorted_wishes:
+    [summary, status] = issue_details.get(url, "No summary available")
+    new_leaderboard += f"| {url} | {summary} | {count} | {status} |\n"
+new_leaderboard += f"\n> Last updated: {date.today().strftime('%Y-%m-%d')}\n"
+print(new_leaderboard)
+
+new_content = re.sub(
+    r"(\| Feature Request \|)(.*?)(> Last updated:)(.*?\n)",
+    new_leaderboard,
+    wishlist_issue.body,
+    flags=re.DOTALL,
+)
+
+wishlist_issue.edit(body=new_content)

.github/workflows/misc-update-wishlist-leaderboard.yml

@@ -0,0 +1,36 @@
+name: Update wishlist leaderboard
+
+on:
+  schedule:
+    # Run every 3 hours
+    - cron:  '0 */3 * * *'
+
+permissions:
+  contents: read
+  issues: write
+
+jobs:
+  update-wishlist-leaderboard:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up Python
+        uses: actions/setup-python@v2
+        with:
+          python-version: '3.x'
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install PyGithub
+      - name: Update developer wishlist
+        env:
+          GH_TOKEN: ${{ github.token }}
+          WISHLIST_REPOSITORY: "paritytech/polkadot-sdk"
+          WISHLIST_ISSUE_NUMBER: "3900"
+        run: python .github/scripts/update-wishlist-leaderboard.py
+      - name: Update user wishlist
+        env:
+          GH_TOKEN: ${{ github.token }}
+          WISHLIST_REPOSITORY: "paritytech/polkadot-sdk"
+          WISHLIST_ISSUE_NUMBER: "3901"
+        run: python .github/scripts/update-wishlist-leaderboard.py