bump actions to v4

Author: marcing

.github/workflows/ci.yml

@@ -35,7 +35,7 @@ jobs:
                     extensions: apcu
                     ini-values: apc.enable_cli=1, opcache.enable=1, opcache.jit=tracing, opcache.jit_buffer_size=128M
             -   name: Cache Composer dependencies
-                uses: actions/cache@v2
+                uses: actions/cache@v4
                 with:
                     path: ~/.composer/cache
                     key: php-${{ matrix.php }}-composer-locked-${{ hashFiles('composer.lock') }}
@@ -58,7 +58,7 @@ jobs:
                     tools: composer:v2, cs2pr
                     coverage: none
             -   name: Cache Composer dependencies
-                uses: actions/cache@v2
+                uses: actions/cache@v4
                 with:
                     path: ~/.composer/cache
                     key: php-composer-locked-${{ hashFiles('composer.lock') }}
@@ -80,7 +80,7 @@ jobs:
                     tools: composer:v2, cs2pr
                     coverage: none
             -   name: Cache Composer dependencies
-                uses: actions/cache@v2
+                uses: actions/cache@v4
                 with:
                     path: ~/.composer/cache
                     key: php-composer-locked-${{ hashFiles('composer.lock') }}