diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 26caf81..a34e727 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -1,23 +1,14 @@
 on:
   pull_request:
-    paths-ignore:
-      - 'docs/**'
-      - 'README.md'
-      - 'CHANGELOG.md'
-      - '.gitignore'
-      - '.gitattributes'
-      - 'infection.json.dist'
-      - 'psalm.xml'
-
+    paths: &paths
+      - 'src/**'
+      - 'tests/**'
+      - '.github/workflows/build.yml'
+      - 'composer.json'
+      - 'phpunit.xml.dist'
   push:
-    paths-ignore:
-      - 'docs/**'
-      - 'README.md'
-      - 'CHANGELOG.md'
-      - '.gitignore'
-      - '.gitattributes'
-      - 'infection.json.dist'
-      - 'psalm.xml'
+    branches: ['master']
+    paths: *paths
 
 name: build
 
@@ -61,10 +52,10 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v7
+        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
 
       - name: Install PHP
-        uses: shivammathur/setup-php@v2
+        uses: shivammathur/setup-php@f3e473d116dcccaddc5834248c87452386958240 # v2
         with:
           php-version: ${{ matrix.php }}
           extensions: ${{ env.extensions }}
@@ -72,23 +63,14 @@ jobs:
           coverage: pcov
           tools: composer:v2
 
-      - name: Determine composer cache directory on Linux
-        if: matrix.os == 'ubuntu-latest'
-        run: echo "COMPOSER_CACHE_DIR=$(composer config cache-dir)" >> $GITHUB_ENV
-
-      - name: Cache dependencies installed with composer
-        uses: actions/cache@v6
-        with:
-          path: ${{ env.COMPOSER_CACHE_DIR }}
-          key: php${{ matrix.php }}-composer-${{ hashFiles('**/composer.json') }}
-          restore-keys: |
-            php${{ matrix.php }}-composer-
-
-      - name: Update composer
-        run: composer self-update
-
-      - name: Install dependencies with composer
-        run: composer update --prefer-dist --no-interaction --no-progress --optimize-autoloader --ansi
+      - name: Install Composer dependencies
+        uses: ramsey/composer-install@65e4f84970763564f46a70b8a54b90d033b3bdda # 4.0.0
 
       - name: Run tests with phpunit
-        run: vendor/bin/phpunit --colors=always
+        run: vendor/bin/phpunit --coverage-clover=coverage.xml --colors=always
+
+      - name: Upload coverage to Codecov.
+        uses: codecov/codecov-action@fb8b3582c8e4def4969c97caa2f19720cb33a72f # v7.0.0
+        with:
+          token: ${{ secrets.CODECOV_TOKEN }}
+          files: ./coverage.xml