Trim off minor versions from otp releases

Author: Josh Price

.travis.yml

@@ -1,13 +1,12 @@
 language: elixir
 elixir:
   - 1.2.3
-  - 1.2.6
+  - 1.2.5
   - 1.3.0-rc.1
 otp_release:
   - 18.2
-  - 18.2.4
-  - 18.3.3
-  - 19.0-rc.1
+  - 18.3
+  - 19.0
 
 before_script:
   - kerl list installations