Bump junit from 4.12 to 4.13.1

diff --git a/pom.xml b/pom.xml
index 5b8bd6f..6ea2b2b 100644
--- a/pom.xml
+++ b/pom.xml
@@ -169,7 +169,7 @@
     <dependency>
       <groupId>junit</groupId>
       <artifactId>junit</artifactId>
-      <version>4.12</version>
+      <version>4.13.1</version>
       <scope>test</scope>
     </dependency>
     <dependency>