Merge #7

7: ci: test on stable r=therealprof a=japaric



Co-authored-by: Jorge Aparicio <jorge@japaric.io>

Author: bors[bot]

.travis.yml

@@ -3,18 +3,18 @@ language: rust
 matrix:
   include:
     - env: TARGET=x86_64-unknown-linux-gnu
-      rust: beta
+      rust: stable
 
     - env: TARGET=thumbv7m-none-eabi
-      rust: beta
+      rust: stable
       if: (branch = staging OR branch = trying) OR (type = pull_request AND branch = master)
 
     - env: TARGET=thumbv7em-none-eabi
-      rust: beta
+      rust: stable
       if: (branch = staging OR branch = trying) OR (type = pull_request AND branch = master)
 
     - env: TARGET=thumbv7em-none-eabihf
-      rust: beta
+      rust: stable
       if: (branch = staging OR branch = trying) OR (type = pull_request AND branch = master)
 
     - env: TARGET=x86_64-unknown-linux-gnu