Update ramsey/composer-install action to v4 (#29)

| datasource  | package                 | from  | to    |
| ----------- | ----------------------- | ----- | ----- |
| github-tags | ramsey/composer-install | 3.0.0 | 4.0.0 |

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/ci.yml

@@ -27,7 +27,7 @@ jobs:
           php-version: "${{ matrix.php-version }}"
           ini-values: "${{ env.INI_VALUES }}"
           tools: composer-normalize,composer-require-checker,composer-unused
-      - uses: "ramsey/composer-install@v3"
+      - uses: "ramsey/composer-install@4.0.0"
 
       - run: "composer validate --strict"
       - run: "composer-normalize --dry-run"
@@ -54,7 +54,7 @@ jobs:
           coverage: "${{ matrix.code-coverage }}"
           php-version: "${{ matrix.php-version }}"
           ini-values: "${{ env.INI_VALUES }}"
-      - uses: "ramsey/composer-install@v3"
+      - uses: "ramsey/composer-install@4.0.0"
 
       - run: "vendor/bin/phpunit --no-coverage --no-logging"
         if: ${{ matrix.code-coverage == 'none' }}
@@ -87,6 +87,6 @@ jobs:
           coverage: "none"
           php-version: "${{ matrix.php-version }}"
           ini-values: "${{ env.INI_VALUES }}"
-      - uses: "ramsey/composer-install@v3"
+      - uses: "ramsey/composer-install@4.0.0"
 
       - run: "vendor/bin/php-cs-fixer fix --verbose --dry-run --diff"