Upgrade actions/cache to v4 in Github workflows.

- [1] https://github.com/google/tsunami-security-scanner-plugins/actions/runs/13678837776/job/38245702857
- [2] https://github.blog/changelog/2024-12-05-notice-of-upcoming-releases-and-breaking-changes-for-github-actions/#actions-cache-v1-v2-and-actions-toolkit-cache-package-closing-down

PiperOrigin-RevId: 733728912
Change-Id: If707a2d862db5c1ff6b4bced4191c2d8bc290d4e

.github/workflows/community-build.yml

@@ -24,7 +24,7 @@ jobs:
         with:
           java-version: ${{ matrix.java }}
       - name: 'Cache Gradle resources'
-        uses: actions/cache@v2
+        uses: actions/cache@v4
         with:
           path: ~/.gradle/caches
           key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle') }}

.github/workflows/doyensec-build.yml

@@ -24,7 +24,7 @@ jobs:
         with:
           java-version: ${{ matrix.java }}
       - name: 'Cache Gradle resources'
-        uses: actions/cache@v2
+        uses: actions/cache@v4
         with:
           path: ~/.gradle/caches
           key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle') }}

.github/workflows/examples-build.yml

@@ -24,7 +24,7 @@ jobs:
         with:
           java-version: ${{ matrix.java }}
       - name: 'Cache Gradle resources'
-        uses: actions/cache@v2
+        uses: actions/cache@v4
         with:
           path: ~/.gradle/caches
           key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle') }}

.github/workflows/google-build.yml

@@ -24,7 +24,7 @@ jobs:
         with:
           java-version: ${{ matrix.java }}
       - name: 'Cache Gradle resources'
-        uses: actions/cache@v2
+        uses: actions/cache@v4
         with:
           path: ~/.gradle/caches
           key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle') }}

.github/workflows/govtech-build.yml

@@ -24,7 +24,7 @@ jobs:
         with:
           java-version: ${{ matrix.java }}
       - name: 'Cache Gradle resources'
-        uses: actions/cache@v2
+        uses: actions/cache@v4
         with:
           path: ~/.gradle/caches
           key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle') }}