Fix workflow triggers

.github/workflows/main.yml

@@ -3,6 +3,14 @@ name: Test
 on:
   push:
   pull_request:
+    branches:
+      # Branches from forks have the form 'user:branch-name' so we only run
+      # this job on pull_request events for branches that look like fork
+      # branches. Without this we would end up running this job twice for non
+      # forked PRs, once for the push and then once for opening the PR.
+      - "**:**"
+  release:
+    types: [published]
 
 jobs:
   test: