Use maven wrapper in integration tests

Needed because the checkstyle plugin could fail with older maven
versions

Author: geoand

.circleci/config.yml

@@ -106,7 +106,7 @@ jobs:
             /snap/bin/microk8s.kubectl config view --raw > /tmp/kubeconfig
             export KUBECONFIG=/tmp/kubeconfig
             cd spring-cloud-kubernetes-integration-tests
-            mvn -Ddocker.host='unix:///var/snap/microk8s/current/docker.sock' -Dimage.registry='localhost:32000' clean package fabric8:build verify -Pfmp,it,spring
+            ../mvnw -Ddocker.host='unix:///var/snap/microk8s/current/docker.sock' -Dimage.registry='localhost:32000' clean package fabric8:build verify -Pfmp,it,spring
       - store_test_results:
           path: $HOME/artifacts/junit/
       - store_artifacts: