Merge pull request #1801 from google/dependabot/maven/proto/junit-junit-4.13.1

Bump junit from 4.12 to 4.13.1 in /proto

Author: eamonnmcmanus

proto/pom.xml

@@ -76,7 +76,7 @@
     <dependency>
       <groupId>junit</groupId>
       <artifactId>junit</artifactId>
-      <version>4.12</version>
+      <version>4.13.1</version>
       <scope>test</scope>
     </dependency>