Use Zulu JDK 17: the Gitea runner cannot reach api.adoptium.net

setup-java's temurin distribution resolves versions through api.adoptium.net,
which fails TLS from the runner (EPROTO) while api.azul.com is reachable.
Any JDK 17 builds the project.

Co-Authored-By: Claude Sonnet 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01JdMNbY5hLR7FjtfEE712xG

.github/workflows/ci.yml

@@ -56,7 +56,7 @@ jobs:
       - name: Set up JDK 17
         uses: actions/setup-java@v4
         with:
-          distribution: temurin
+          distribution: zulu
           java-version: '17'
           cache: gradle
 

.github/workflows/net-check.yml

@@ -1,12 +0,0 @@
-name: Net check
-on: workflow_dispatch
-jobs:
-  net:
-    runs-on: ubuntu-latest
-    steps:
-      - name: Probe outbound HTTPS from the runner
-        run: |
-          cat /etc/os-release | head -2; command -v java node npm curl git || true
-          for u in https://api.azul.com/metadata/v1/zulu/packages/?java_version=17\&os=linux\&arch=x64\&archive_type=tar.gz\&java_package_type=jdk\&latest=true https://cdn.azul.com https://corretto.aws/downloads/latest/amazon-corretto-17-x64-linux-jdk.tar.gz https://aka.ms/download-jdk/microsoft-jdk-17-linux-x64.tar.gz https://api.adoptium.net/v3/info/available_releases https://github.com/adoptium/temurin17-binaries/releases https://objects.githubusercontent.com https://download.oracle.com/java/17/latest/jdk-17_linux-x64_bin.tar.gz https://api.foojay.io/disco/v3.0/packages; do
-            printf '%s -> ' "$u"; curl -sS -o /dev/null -m 15 -w '%{http_code}\n' "$u" 2>&1 | tail -1
-          done

.github/workflows/release.yml

@@ -42,7 +42,7 @@ jobs:
       - name: Set up JDK 17
         uses: actions/setup-java@v4
         with:
-          distribution: temurin
+          distribution: zulu
           java-version: '17'
           cache: gradle