gradle version 5 (#17)

Author: dgrove-oss

gradle/wrapper/gradle-wrapper.properties

@@ -14,9 +14,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
-
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-4.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-5.5.1-bin.zip