Fix IT failure: plexus-compiler-javac-errorprone 2.8.2 updated the Error Prone library to version >= 2.0.6, which requires JDK 8 (https://github.com/google/error-prone/issues/369).

git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1797098 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/src/it/error-prone-compiler/invoker.properties b/src/it/error-prone-compiler/invoker.properties
index 564861a..5784b9b 100644
--- a/src/it/error-prone-compiler/invoker.properties
+++ b/src/it/error-prone-compiler/invoker.properties
@@ -15,6 +15,6 @@
 # specific language governing permissions and limitations
 # under the License.
 
-invoker.java.version = 1.7+
+invoker.java.version = 1.8+
 invoker.goals = clean compile
 invoker.buildResult = failure