Update to Surefire-M5 and change include pattern

fixes: #41

pom.xml

@@ -36,12 +36,13 @@
       <!-- Only required if names of spec classes don't match default Surefire patterns (`*Test` etc.) -->
       <plugin>
         <artifactId>maven-surefire-plugin</artifactId>
-        <version>3.0.0-M4</version>
+        <version>3.0.0-M5</version>
         <configuration>
+          <useModulePath>false</useModulePath> <!-- https://issues.apache.org/jira/browse/SUREFIRE-1809 -->
           <useFile>false</useFile>
           <includes>
-            <include>**/*Test.java</include>
+            <include>**/*Test</include>
-            <include>**/*Spec.java</include>
+            <include>**/*Spec</include>
           </includes>
         </configuration>
       </plugin>
@@ -61,7 +62,7 @@
       <dependency>
         <groupId>org.spockframework</groupId>
         <artifactId>spock-bom</artifactId>
-        <version>2.0-M4-groovy-3.0</version>
+        <version>2.0-M5-groovy-3.0</version>
         <type>pom</type>
         <scope>import</scope>
       </dependency>