Use JDK 17 for tests

.github/workflows/push.yml

@@ -17,9 +17,9 @@ jobs:
         git tag ${BNUM}
         git config --global user.name "Build Uploader"
         git push https://Anuken:${{ secrets.API_TOKEN_GITHUB }}@github.com/Anuken/MindustryBuilds ${BNUM}
-    - name: Set up JDK 16
+    - name: Set up JDK 17
       uses: actions/setup-java@v1
       with:
-        java-version: 16
+        java-version: 17
     - name: Run unit tests
       run: ./gradlew clean cleanTest test