Bump ramsey/composer-install from 3 to 4

Bumps [ramsey/composer-install](https://github.com/ramsey/composer-install) from 3 to 4.
- [Release notes](https://github.com/ramsey/composer-install/releases)
- [Commits](ramsey/composer-install@v3...v4)

---
updated-dependencies:
- dependency-name: ramsey/composer-install
  dependency-version: '4'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/phpcs.yml

@@ -29,6 +29,6 @@ jobs:
           coverage: none
           tools: composer, cs2pr
       - name: Install Composer dependencies for PHP
-        uses: ramsey/composer-install@v3
+        uses: ramsey/composer-install@v4
       - name: Detect coding standard violations
         run: ./vendor/bin/phpcs

.github/workflows/phpunit.yml

@@ -60,7 +60,7 @@ jobs:
           coverage: none
 
       - name: Install Composer dependencies
-        uses: ramsey/composer-install@v3
+        uses: ramsey/composer-install@v4
 
       - name: Setup Test Environment
         run: bash bin/install-wp-tests.sh wordpress_test root root 127.0.0.1 ${{ matrix.wp-version }}