Run GitHub Actions on PRs

Also:

- Set explicit permissions to read for better security. Workflows run
  with extended set of permissions by default. By specifying
  any permission explicitly, all others are set to none.
- Update actions to prevent deprecation warning messages
- Remove redundant `gem install bundler` (bundler is already available after
  setup-ruby action)
- Use Python 3

Ref: https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions#permissions

.github/workflows/integration_test.yml

@@ -1,6 +1,13 @@
 name: Integration Tests
 
-on: [push]
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+permissions:
+  contents: read
 
 jobs:
   build:
@@ -11,9 +18,9 @@ jobs:
     timeout-minutes: 20
     steps:
     - name: Checkout
-      uses: actions/checkout@v2
+      uses: actions/checkout@v4
     - name: Checkout test app
-      uses: actions/checkout@v2
+      uses: actions/checkout@v4
       with:
         repository: jamesmartin/inline_svg_test_app
         ref: ${{ matrix.test-branch }}
@@ -22,10 +29,9 @@ jobs:
       uses: ruby/setup-ruby@v1
       with:
         ruby-version: 2.7.7
+        bundler-cache: true
     - name: Build local gem
       run: |
-        gem install bundler
-        bundle install --jobs 4 --retry 3
         bundle exec rake build
     - name: Use the local gem in the test App
       id: uselocalgem

.github/workflows/rails_6_webpacker_integration_tests.yaml

@@ -1,19 +1,26 @@
 name: Rails 6 Webpacker Integration Tests (unreliable)
 
-on: [push]
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+permissions:
+  contents: read
 
 jobs:
   build:
 
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     strategy:
       matrix:
         test-branch: [rails6-webpacker]
     steps:
     - name: Checkout
-      uses: actions/checkout@v2
+      uses: actions/checkout@v4
     - name: Checkout test app
-      uses: actions/checkout@v2
+      uses: actions/checkout@v4
       with:
         repository: jamesmartin/inline_svg_test_app
         ref: ${{ matrix.test-branch }}
@@ -22,14 +29,13 @@ jobs:
       uses: ruby/setup-ruby@v1
       with:
         ruby-version: 3.1
+        bundler-cache: true
     - name: Build local gem
       run: |
-        gem install bundler
-        bundle install --jobs 4 --retry 3
         bundle exec rake build
     - name: Use the local gem in the test App
       id: uselocalgem
-      uses: jacobtomlinson/gha-find-replace@0.1.1
+      uses: jacobtomlinson/gha-find-replace@v3
       with:
         find: "gem 'inline_svg'"
         replace: "gem 'inline_svg', path: '${{github.workspace}}'"
@@ -42,7 +48,7 @@ jobs:
         cd $GITHUB_WORKSPACE/test_app
         bundle install --jobs 4 --retry 3
     - name: Set up Node.js 16.x
-      uses: actions/setup-node@v2
+      uses: actions/setup-node@v4
       with:
         node-version: 16
       if: matrix.test-branch == 'rails6-webpacker'
@@ -53,7 +59,7 @@ jobs:
     - name: Generate Webpacker config
       run: |
         cd $GITHUB_WORKSPACE/test_app
-        CXXFLAGS="--std=c++17" yarn install --check-files
+        yarn install --check-files
         bundle exec rake webpacker:compile
       if: matrix.test-branch == 'rails6-webpacker'
     - name: Test

.github/workflows/ruby.yml

@@ -1,20 +1,26 @@
 name: Ruby
 
-on: [push]
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+permissions:
+  contents: read
 
 jobs:
   build:
 
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
     - name: Set up Ruby 2.7
       uses: ruby/setup-ruby@v1
       with:
         ruby-version: 2.7.7
-    - name: Build and test with Rake
+        bundler-cache: true
+    - name: Test with Rake
       run: |
-        gem install bundler
-        bundle install --jobs 4 --retry 3
         bundle exec rake