Update dependency junit:junit to v4.13.1 (#266)

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build.gradle

@@ -355,7 +355,7 @@ dependencies {
     testImplementation group: 'org.objenesis', name: 'objenesis', version: '3.0.1'
     testImplementation group: 'org.hamcrest', name: 'hamcrest-library', version: '2.1'
     testImplementation group: 'org.hamcrest', name: 'hamcrest', version: '2.1'
-    testImplementation group: 'junit', name: 'junit', version: '4.12'
+    testImplementation group: 'junit', name: 'junit', version: '4.13.1'
 }
 
 configurations.each {