Updated JDK to 21 for Github Actions

Author: ribafish

.github/workflows/build-verification.yml

@@ -12,10 +12,10 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v4
-      - name: Set up JDK 8
+      - name: Set up JDK 21
         uses: actions/setup-java@v4
         with:
-          java-version: '8'
+          java-version: '21'
           distribution: 'adopt'
       - name: Set up Gradle
         uses: gradle/actions/setup-gradle@v4

.github/workflows/cross-platform-testing-build-from-source.yml

@@ -13,10 +13,10 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v4
-      - name: Set up JDK 8
+      - name: Set up JDK 21
         uses: actions/setup-java@v4
         with:
-          java-version: '8'
+          java-version: '21'
           distribution: 'adopt'
       - name: Set up Gradle
         uses: gradle/actions/setup-gradle@v4

.github/workflows/development-release.yml

@@ -15,10 +15,10 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v4
-      - name: Set up JDK 8
+      - name: Set up JDK 21
         uses: actions/setup-java@v4
         with:
-          java-version: '8'
+          java-version: '21'
           distribution: 'adopt'
       - name: Set up Gradle
         uses: gradle/actions/setup-gradle@v4

.github/workflows/production-release.yml

@@ -15,10 +15,10 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v4
-      - name: Set up JDK 8
+      - name: Set up JDK 21
         uses: actions/setup-java@v4
         with:
-          java-version: '8'
+          java-version: '21'
           distribution: 'adopt'
       - name: Set up Gradle
         uses: gradle/actions/setup-gradle@v4