Add release.yaml to help auto-populate release notes

* Auto-populated release notes have a nice way of highlighting
new contributors and sorting dependency updates to the bottom.
I'll still keep the hand-written changelog notes at the top
because they're written for those who want a better summary
than just a bunch of PR titles
* Remove the PR template since its often unused

.github/release.yaml

@@ -0,0 +1,12 @@
+changelog:
+  categories:
+    - title: Contributions
+      labels:
+        - '*'
+      exclude:
+        labels:
+          - dependencies
+          - no-release-note
+    - title: Dependencies
+      labels:
+        - dependencies