chore: pin GitHub Actions to specific commit hashes

- actions/checkout@v4 -> v4.2.2
- actions/setup-java@v3 -> v3.13.0
- actions/cache@v2 -> v2
- ruby/setup-ruby@v1 -> v1.227.0

Author: capytan

.github/workflows/pr_check.yml

@@ -6,13 +6,13 @@ jobs:
   danger:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
       - name: Setup Java
-        uses: actions/setup-java@v3
+        uses: actions/setup-java@0ab4596768b603586c0de567f2430c30f5b0d2b0 # v3.13.0
         with:
           distribution: 'temurin'
           java-version: '17'
-      - uses: actions/cache@v2
+      - uses: actions/cache@8492260343ad570701412c2f464a5877dc76bace # v2
         with:
           path: |
             ~/.gradle/caches
@@ -24,7 +24,7 @@ jobs:
         run: |
           ./gradlew androidDependencies --no-daemon
 
-      - uses: ruby/setup-ruby@v1
+      - uses: ruby/setup-ruby@1a615958ad9d422dd932dc1d5823942ee002799f # v1.227.0
         with:
           ruby-version: 3.1
           bundler-cache: true
@@ -36,13 +36,13 @@ jobs:
   unit_test:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
       - name: Setup Java
-        uses: actions/setup-java@v3
+        uses: actions/setup-java@0ab4596768b603586c0de567f2430c30f5b0d2b0 # v3.13.0
         with:
           distribution: 'temurin'
           java-version: '17'
-      - uses: actions/cache@v2
+      - uses: actions/cache@8492260343ad570701412c2f464a5877dc76bace # v2
         with:
           path: |
             ~/.gradle/caches

.github/workflows/unit_test.yml

@@ -9,13 +9,13 @@ jobs:
   unit_test:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
       - name: Setup Java
-        uses: actions/setup-java@v3
+        uses: actions/setup-java@0ab4596768b603586c0de567f2430c30f5b0d2b0 # v3.13.0
         with:
           distribution: 'temurin'
           java-version: '17'
-      - uses: actions/cache@v2
+      - uses: actions/cache@8492260343ad570701412c2f464a5877dc76bace # v2
         with:
           path: |
             ~/.gradle/caches