Merge pull request #59 from getong/update_test_erlang_version

add erlang 19, 20 for test
diff --git a/.travis.yml b/.travis.yml
index 225b83d..8f55847 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,6 +1,8 @@
 sudo: false
 language: erlang
 otp_release:
+  - 20.0
+  - 19.3
   - 18.3
   - 17.3
   - 17.1