[CI] Install dependencies only once

- Use ramsey/composer-install action with dependency matrix
- Ensure composer validate runs before install in both jobs

Author: OskarStark

.github/workflows/pipeline.yml

@@ -28,11 +28,9 @@ jobs:
       - name: Install Composer
         uses: "ramsey/composer-install@v3"
         with:
+          composer-options: "--no-scripts"
           dependency-versions: "${{ matrix.dependencies }}"
 
-      - name: Install PHP Dependencies
-        run: composer install --no-scripts
-
       - name: Tests
         run: vendor/bin/phpunit --exclude-group inspector
 
@@ -53,10 +51,8 @@ jobs:
 
       - name: Install Composer
         uses: "ramsey/composer-install@v3"
-
-      - name: Install PHP Dependencies
-        run: composer install --no-scripts
-
+        with:
+          composer-options: "--no-scripts"
       - name: Code Style PHP
         run: vendor/bin/php-cs-fixer fix --dry-run