Setup Java environment for openapi-generator in the github action

.github/workflows/generate.yml

@@ -25,6 +25,10 @@ jobs:
     steps:
       - name: Checkout C
         uses: actions/checkout@v3
+      - uses: actions/setup-java@v3
+          with:
+          distribution: 'temurin'
+          java-version: '17'
       - name: Checkout Gen
         run: |
           git clone https://github.com/kubernetes-client/gen