Bump gradle to 6.4.1

Author: joshka

gradle/wrapper/gradle-wrapper.properties

@@ -1,5 +1,5 @@
-#Tue Dec 10 00:17:56 PST 2019
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.0.1-all.zip
+#Fri May 29 16:41:13 PDT 2020
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.4.1-all.zip
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStorePath=wrapper/dists