[TEST] Update Travis testing matrix with 6.2

Author: polyfractal

.travis.yml

@@ -17,20 +17,22 @@ sudo: true
 matrix:
   fast_finish: true
   include:
-    - php: 7.0
-      env: ES_VERSION="6.0"
     - php: 7.0
       env: ES_VERSION="6.1"
+    - php: 7.0
+      env: ES_VERSION="6.2"
 
-    - php: 7.1
-      env: ES_VERSION="6.0"
     - php: 7.1
       env: ES_VERSION="6.1"
+    - php: 7.1
+      env: ES_VERSION="6.2"
 
     - php: 7.2
       env: ES_VERSION="6.0"
     - php: 7.2
       env: ES_VERSION="6.1"
+    - php: 7.2
+      env: ES_VERSION="6.2"
     - php: 7.2
       env: ES_VERSION="6.x"