Upgrade junit dependency to 4.13.1

PiperOrigin-RevId: 336966883

Author: cushon

pom.xml

@@ -125,7 +125,7 @@
  <dependency>
  <groupId>junit</groupId>
  <artifactId>junit</artifactId>
- <version>4.12</version>
+ <version>4.13.1</version>
  <scope>test</scope>
  </dependency>
  <dependency>