Stable toolchain is only one left, OSX testing is removed.

nullvideo · nullvideo · commit 9a53bc0f37c7 · 2019-11-05T08:39:19.000+05:30
diff --git a/.travis.yml b/.travis.yml
@@ -1,6 +1,2 @@
-os:
-  - linux
-  - osx
-language: rust
-rust:
-  - stable
+os: linux
+language: rust
