chore(ci): fix builds failing due to outdated action

Author: hannojg

.github/workflows/build-android.yml

@@ -49,7 +49,7 @@ jobs:
         run: yarn install --frozen-lockfile --cwd example
 
       - name: Restore Gradle cache
-        uses: actions/cache@v2
+        uses: actions/cache@v4
         with:
           path: |
             ~/.gradle/caches

.github/workflows/build-ios.yml

@@ -56,7 +56,7 @@ jobs:
           working-directory: example
 
       - name: Restore Pods cache
-        uses: actions/cache@v2
+        uses: actions/cache@v4
         with:
           path: |
             example/ios/Pods