Bump Gradle to latest 5.x version 5.6.4
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index 3a54a33..0ebb310 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-5.6.3-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-5.6.4-all.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists