ci: fix usage of Java 11 which should have been 17 (#239)

Author: jponge

.github/workflows/build-main.yml

@@ -38,7 +38,7 @@ jobs:
         name: Set up JDK 11
         with:
           distribution: temurin
-          java-version: 11
+          java-version: 17
           cache: maven
       - name: Compatibility Check
         run: ./mvnw -s .github/maven-ci-settings.xml -B install revapi:check@check-compatibility -DskipTests -fae