Add elixir 1.10 to ci build (#155)

* Add elixir 1.10 to ci build

Also change other elixir versions to be the latest patch release for that minor version

* Use 22.2 since 22.3 is not yet ready on travis

Author: axelson

.travis.yml

@@ -22,7 +22,9 @@ matrix:
     - otp_release: 20.3
       elixir: 1.7.4
     - otp_release: 21.3
-      elixir: 1.8.1
+      elixir: 1.8.2
     - otp_release: 22.0
-      elixir: 1.9.1
+      elixir: 1.9.4
+    - otp_release: 22.2
+      elixir: 1.10.2
       env: CHECK_FORMATTED=1