chore(deps): update dependency junit:junit to v4.13 (googleapis#1462)

Author: renovate-bot

pom.xml

@@ -89,7 +89,7 @@
       <dependency>
         <groupId>junit</groupId>
         <artifactId>junit</artifactId>
-        <version>4.12</version>
+        <version>4.13</version>
       </dependency>
       <dependency>
         <groupId>com.google.appengine</groupId>