Bump junit from 4.13 to 4.13.1 in /exonum-java-binding (#1631)

Author: dependabot[bot]

exonum-java-binding/pom.xml

@@ -122,7 +122,7 @@
     <guice.version>4.2.3</guice.version>
     <log4j.version>2.13.3</log4j.version>
     <hamcrest.version>2.2</hamcrest.version>
-    <junit.version>4.13</junit.version>
+    <junit.version>4.13.1</junit.version>
     <junit.jupiter.version>5.6.2</junit.jupiter.version>
     <protobuf.version>3.11.0</protobuf.version>
     <mockito.version>3.4.4</mockito.version>