assertj-core must be test scope (#826)

Signed-off-by: Olivier Lamy <olamy@apache.org>

Author: olamy

surefire-providers/surefire-junit-platform/pom.xml

@@ -117,6 +117,7 @@
     <dependency>
       <groupId>org.assertj</groupId>
       <artifactId>assertj-core</artifactId>
+      <scope>test</scope>
     </dependency>
     <dependency>
       <groupId>org.mockito</groupId>