upgrade gradle from 5.0 to 5.4 (#126)

* update gradle from 5.0 to 5.4 to match geode and geode-examples
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index 5e4ca85..51d5ca2 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -3,4 +3,4 @@
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-5.0-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-5.4-all.zip