Disable caching in CI

Sh3Rm4n · Sh3Rm4n · commit bcd0f4a39f5f · 2020-03-07T14:08:47.000+01:00
For now this seems to time out the travis instance, so the build will not
succeed. Disable it for now until this issue is resolved.
diff --git a/.travis.yml b/.travis.yml
@@ -4,8 +4,6 @@ rust:
   - stable
   - nightly
 
-cache: cargo
-
 matrix:
   allow_failures:
     - rust: nightly
