removed unsupport django version from travis

Author: agusmakmun

.travis.yml

@@ -23,10 +23,6 @@ matrix:
       env: DJANGO=2.1.*
     - python: 3.5
       env: DJANGO=2.2.*
-    - python: 3.5
-      env: DJANGO=3.0.*
-    - python: 3.5
-      env: DJANGO=3.1.*
 
     - python: 3.6
       env: DJANGO=1.10.*