GH Actions: update a few links in inline comments

... as the old URLs are no longer valid.

Author: jrfnl

.github/workflows/cs.yml

@@ -29,7 +29,7 @@ jobs:
           tools: cs2pr
 
       # Install dependencies and handle caching in one go.
-      # @link https://github.com/marketplace/actions/install-composer-dependencies
+      # @link https://github.com/marketplace/actions/install-php-dependencies-with-composer
       - name: Install Composer dependencies
         uses: "ramsey/composer-install@v2"
         with:

.github/workflows/test.yml

@@ -58,7 +58,7 @@ jobs:
         run: composer remove --dev php-parallel-lint/php-code-style --no-update --no-interaction
 
       # Install dependencies and handle caching in one go.
-      # @link https://github.com/marketplace/actions/install-composer-dependencies
+      # @link https://github.com/marketplace/actions/install-php-dependencies-with-composer
       - name: Install Composer dependencies - normal
         if: ${{ matrix.experimental == false }}
         uses: "ramsey/composer-install@v2"