chore: Update pinned nightly so compiling works again

The nightlies of 2018-06-22 don't work (rust-lang/rust#51699, https://twitter.com/RustStatus/status/1010240719527739392?s=19).
clap-rs · Jun 23, 2018 · 9f183d2 · 9f183d2
1 parent 356c69e
commit 9f183d2
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/.travis.yml b/.travis.yml
@@ -3,7 +3,7 @@ language: rust
 cache: cargo
 rust:
   - nightly
-  - nightly-2017-10-11
+  - nightly-2018-06-19
   - beta
   - stable
   - 1.21.0