Do not overwrite .mvn/maven.config but contribute to it

Author: gsmet

.github/workflows/ci-actions-incremental.yml

@@ -509,7 +509,7 @@ jobs:
           # the format of this file is specific: it's one option per line, thus the weird formatting in matrix-jvm-tests.json
           # see https://maven.apache.org/configure.html#a.mvn.2Fmaven.config_file.3A
           # IMPORTANT: we cannot simply replace all spaces with new lines as we have a module with spaces in the name (to test spaces are supported)
-          echo -e "$MATRIX_JAVA_MODULES" > .mvn/maven.config
+          echo -e "$MATRIX_JAVA_MODULES" >> .mvn/maven.config
           ./mvnw $COMMON_MAVEN_ARGS $COMMON_TEST_MAVEN_ARGS $PTS_MAVEN_ARGS clean install -Dsurefire.timeout=1200 -Dno-test-kubernetes ${{ matrix.java.maven_args }}
       - name: Clean Gradle temp directory
         if: always()