Ensure correct version of gradle (#65)

* Ensure correct version of gradle

* Upgrade to 5.x gradle

Author: ferhatelmas

.travis.yml

@@ -4,11 +4,13 @@ jdk:
 cache:
   directories:
     - $HOME/.m2
+    - $HOME/.gradle
 env:
   global:
     - secure: TmI+K6gSOfDy5oa5EgLCGijimKdR5cHAwM6RASDegTjlRQ/sWVf8BNF4IPJHnAYFWNCgyX6vLdfPS3IJNrYS9iI1Er2a1Ctcq1TbCZfZpn4eIj8mcUXxr2Fo6hLJh2KeuXj3OQwfUy/Jul1Own/9R5YoVDJYD0ntnt1HJgFqq+0=
     - secure: DethMgIykOufLLQn9Jykmg7rdvZp4ONXD4A1XVQNaEVQytv20Fb2QidEPmVEocuDmpmU6SjWNMhAeBdlWnyGB4lECMG9594HJpSnNkyFQzzsfSWdOwHixiUCuD+rMJlEPRJDM4ayxhilPnK1gkycKBAZ1gtutriC4O/BdEOCN6A=
     - secure: F6jGxeoyhD1tmC0ovRW2RqeEQDN5t5Kfqktmtcj0Lz3S4ddgzMwC6RYKyYiiu9T3FSfh/hEMrx2SrMK+Neu2ctfYflNibUjgZJVPZHR7DA3S+g30teyj10XWspb6+OLC7U0DnGbdLee/w0KkuugQHYNv1aM9oEPtLWi+3VpvIIU=
-script: mvn clean install -DskipITs=false
+script:
+  - gradle test
 #after_success:
 #- ".travis/publish.sh"

README.md

@@ -43,7 +43,7 @@ Javadocs are available [here](https://getstream.github.io/stream-java/).
 
 ### Building & Testing
 
-Run `gradle wrapper --gradle-version 4.10.3` to generate gradle wrapper files
+Run `gradle wrapper --gradle-version 5.1.1` to generate gradle wrapper files
 
 Run `gradle test` to execute integration tests