add script to gen release notes from github.

Signed-off-by: Terence Parr <parrt@antlr.org>

scripts/github_release_notes.py

@@ -0,0 +1,47 @@
+# Get github issues / PR for a release
+# Exec with "python github_release_notes.py YOUR_GITHUB_API_ACCESS_TOKEN 2.1.0"
+
+from github import Github
+from collections import Counter
+import sys
+
+TOKEN=sys.argv[1]
+MILESTONE=sys.argv[2]
+g = Github(login_or_token=TOKEN)
+
+# Then play with your Github objects:
+org = g.get_user("parrt")
+repo = org.get_repo("dtreeviz")
+milestone = [x for x in repo.get_milestones() if x.title==MILESTONE]
+milestone = milestone[0]
+
+issues = repo.get_issues(state="closed", milestone=milestone, sort="created", direction="desc")
+
+# dump bugs fixed
+print()
+print("## Issues fixed")
+for x in issues:
+    labels = [l.name for l in x.labels]
+    if x.pull_request is None and not ("type:improvement" in labels or "type:feature" in labels):
+        print("* [%s](%s) (%s)" % (x.title, x.html_url, ", ".join([l.name for l in x.labels])))
+
+# dump improvements closed for this release (issues or pulls)
+print()
+print("## Improvements, features")
+for x in issues:
+    labels = [l.name for l in x.labels]
+    if ("enhancement" in labels):
+        print("* [%s](%s) (%s)" % (x.title, x.html_url, ", ".join(labels)))
+
+# dump contributors
+print()
+print("## Contributors")
+user_counts = Counter([x.user.login for x in issues])
+users = {x.user.login:x.user for x in issues}
+for login,count in user_counts.most_common(10000):
+    name = users[login].name
+    logins = f" ({users[login].login})"
+    if name is None:
+        name = users[login].login
+        logins = ""
+    print(f"* {count:3d} items: [{name}]({users[login].html_url}){logins}")