Update AGP and Gradle wrapper (#577)

Reflects updating Android Studio to the latest stable version (3.6).

build.gradle

@@ -30,7 +30,7 @@ buildscript {
         espressoVersion = '3.1.1'
         fragmentVersion = '1.1.0-alpha09'
         glideVersion = '4.10.0'
-        gradleVersion = '3.5.1'
+        gradleVersion = '3.6.0'
         gsonVersion = '2.8.2'
         junitVersion = '4.12'
         kotlinVersion = '1.3.41'

gradle/wrapper/gradle-wrapper.properties

@@ -1,21 +1,6 @@
-#
-# Copyright 2018 Google LLC
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     https://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-#
-#Thu Aug 22 10:20:57 PDT 2019
+#Tue Feb 25 10:13:19 PST 2020
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-5.4.1-all.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-5.6.4-all.zip