[Java] Upgrade to Gradle 5.6.3.

Author: mjpt777

build.gradle

@@ -767,6 +767,6 @@ task uploadToMavenCentral {
 }
 
 wrapper {
-    gradleVersion = '5.6.2'
+    gradleVersion = '5.6.3'
     distributionType = 'ALL'
 }

gradle/wrapper/gradle-wrapper.properties

@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-5.6.2-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-5.6.3-all.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists