fix: do not trigger build workflows after merging to main or for release PRs

Since all merges to the main branch must be a fast-forward rebase, CI
builds should not be run when merged to main. They are run via the
pull request before merging.

The continuous_integration workflow should be triggered for pull requests
targeting main.

The experimental_ruby_builds workflow should only be triggered manually via
the GitHub UI

Author: jcouball

.github/workflows/continuous_integration.yml

@@ -1,9 +1,6 @@
 name: Continuous Integration
 
 on:
-  push:
-    branches: [main]
-
   pull_request:
     branches: [main]
 
@@ -26,6 +23,10 @@ jobs:
   build:
     name: Ruby ${{ matrix.ruby }} on ${{ matrix.operating-system }}
 
+    if: >-
+      github.event_name == 'workflow_dispatch' ||
+      (github.event_name == 'pull_request' && !startsWith(github.event.pull_request.head.ref, 'release-please--'))
+
     runs-on: ${{ matrix.operating-system }}
     continue-on-error: true
 

.github/workflows/enforce_conventional_commits.yml

@@ -9,6 +9,10 @@ jobs:
   commit-lint:
     name: Verify Conventional Commits
 
+    if: >-
+      github.event_name == 'workflow_dispatch' ||
+      (github.event_name == 'pull_request' && !startsWith(github.event.pull_request.head.ref, 'release-please--'))
+
     runs-on: ubuntu-latest
 
     steps:

.github/workflows/experimental_ruby_builds.yml

@@ -1,9 +1,6 @@
 name: Experimental Ruby Builds
 
 on:
-  push:
-    branches: [main]
-
   workflow_dispatch:
 
 env: