Upgrade GitHub Actions workflows to use Java 21 and update artifact upload action

- Update Java version to 21 in all GitHub Actions workflows (release, ci-client, ci).
- Update the `actions/upload-artifact` action version from v2 to v4.

Author: BobbyESP

.github/workflows/ci-client.yml

@@ -24,15 +24,15 @@ jobs:
         uses: actions/setup-java@v2
         with:
           distribution: 'adopt'
-          java-version: '17'
+          java-version: '21'
       - name: Install curl
         run: sudo apt-get install -y curl libcurl4-openssl-dev
       - name: Verify Android
         run: ./gradlew testDebugUnitTest
       - name: Verify JVM/JS
         run: ./gradlew jvmTest
       - name: Archive test results
-        uses: actions/upload-artifact@v2
+        uses: actions/upload-artifact@v4
         with:
           name: code-coverage-report
           path: build/reports

.github/workflows/ci.yml

@@ -16,19 +16,19 @@ jobs:
     steps:
     - name: Check out repo
       uses: actions/checkout@v2
-    - name: Install java 11
+    - name: Install java 21
       uses: actions/setup-java@v2
       with:
         distribution: 'adopt'
-        java-version: '17'
+        java-version: '21'
     - name: Install curl
       run: sudo apt-get install -y curl libcurl4-openssl-dev
     - name: Test android
       run: ./gradlew testDebugUnitTest
     - name: Test jvm
       run: ./gradlew jvmTest
     - name: Archive test results
-      uses: actions/upload-artifact@v2
+      uses: actions/upload-artifact@v4
       if: always()
       with:
         name: code-coverage-report

.github/workflows/release.yml

@@ -29,11 +29,11 @@ jobs:
     steps:
       - name: Check out repo
         uses: actions/checkout@v2
-      - name: Install java 11
+      - name: Install java 21
         uses: actions/setup-java@v2
         with:
           distribution: 'adopt'
-          java-version: '17'
+          java-version: '21'
       - name: Install curl
         run: sudo apt-get install -y curl libcurl4-openssl-dev
       - name: Verify Android
@@ -43,7 +43,7 @@ jobs:
       - name: Publish JVM/Linux/Android
         run: ./gradlew publishKotlinMultiplatformPublicationToNexusRepository publishJvmPublicationToNexusRepository publishAndroidPublicationToNexusRepository publishLinuxX64PublicationToNexusRepository publishJsPublicationToNexusRepository
       - name: Archive test results
-        uses: actions/upload-artifact@v2
+        uses: actions/upload-artifact@v4
         with:
           name: code-coverage-report
           path: build/reports
@@ -55,11 +55,11 @@ jobs:
     steps:
       - name: Check out repo
         uses: actions/checkout@v2
-      - name: Install java 11
+      - name: Install java 21
         uses: actions/setup-java@v2
         with:
           distribution: 'adopt'
-          java-version: '17'
+          java-version: '21'
       - name: Publish macOS/iOS
         run: ./gradlew publishMacosX64PublicationToNexusRepository publishIosX64PublicationToNexusRepository publishIosArm64PublicationToNexusRepository
   release_windows:
@@ -69,11 +69,11 @@ jobs:
     steps:
       - name: Check out repo
         uses: actions/checkout@v2
-      - name: Install java 11
+      - name: Install java 21
         uses: actions/setup-java@v2
         with:
           distribution: 'adopt'
-          java-version: '17'
+          java-version: '21'
       - run: choco install curl
       - name: Publish windows
         run: ./gradlew publishMingwX64PublicationToNexusRepository
@@ -83,11 +83,11 @@ jobs:
     steps:
       - name: Check out repo
         uses: actions/checkout@v2
-      - name: Install java 11
+      - name: Install java 21
         uses: actions/setup-java@v2
         with:
           distribution: 'adopt'
-          java-version: '17'
+          java-version: '21'
       - name: Build docs
         run: ./gradlew dokkaHtml
       - name: Push docs to docs repo