Update GitHub action version

Author: alistair3149

.github/workflows/ci.yml

@@ -48,7 +48,7 @@ jobs:
 
       - name: Cache MediaWiki
         id: cache-mediawiki
-        uses: actions/cache@v2
+        uses: actions/cache@v4
         with:
           path: |
             mediawiki
@@ -57,12 +57,12 @@ jobs:
           key: mw_${{ matrix.mw }}-php${{ matrix.php }}-v3
 
       - name: Cache Composer cache
-        uses: actions/cache@v2
+        uses: actions/cache@v4
         with:
           path: ~/.composer/cache
           key: composer-php${{ matrix.php }}
 
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
         with:
           path: EarlyCopy
 
@@ -71,7 +71,7 @@ jobs:
         working-directory: ~
         run: bash EarlyCopy/.github/workflows/installMediaWiki.sh ${{ matrix.mw }} WikibaseEdtf
 
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
         with:
           path: mediawiki/extensions/WikibaseEdtf