Bump ramsey/composer-install from 1 to 3 (#1152)

Bumps [ramsey/composer-install](https://github.com/ramsey/composer-install) from 1 to 3.
- [Release notes](https://github.com/ramsey/composer-install/releases)
- [Commits](ramsey/composer-install@v1...v3)

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/phpunit.yml

@@ -37,7 +37,7 @@ jobs:
           extensions: mysql
 
       - name: Install Composer dependencies for PHP
-        uses: "ramsey/composer-install@v1"
+        uses: "ramsey/composer-install@v3"
 
       - name: Setup Test Environment
         run: bash bin/install-wp-tests.sh wordpress_test root root 127.0.0.1 ${{ matrix.wp-version }}