Update to Gradle 6.3 RC4.

Change-Id: I9b0409077b15d43c7051eb477e4b1b6de5ff0805
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index 84a9066..3724ca3 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-6.2.2-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.3-rc-4-all.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists