CI: test on beta

Author: japaric

.travis.yml

@@ -2,31 +2,34 @@ language: rust
 
 matrix:
   include:
+    - env: TARGET=x86_64-unknown-linux-gnu
+      rust: beta
+
+    - env: TARGET=thumbv7m-none-eabi
+      rust: beta
+      if: (branch = staging OR branch = trying) OR (type = pull_request AND branch = master)
+
+    - env: TARGET=thumbv7em-none-eabi
+      rust: beta
+      if: (branch = staging OR branch = trying) OR (type = pull_request AND branch = master)
+
+    - env: TARGET=thumbv7em-none-eabihf
+      rust: beta
+      if: (branch = staging OR branch = trying) OR (type = pull_request AND branch = master)
+
     - env: TARGET=x86_64-unknown-linux-gnu
       rust: nightly
 
     - env: TARGET=thumbv7m-none-eabi
       rust: nightly
-      addons:
-        apt:
-          packages:
-            - gcc-arm-none-eabi
       if: (branch = staging OR branch = trying) OR (type = pull_request AND branch = master)
 
     - env: TARGET=thumbv7em-none-eabi
       rust: nightly
-      addons:
-        apt:
-          packages:
-            - gcc-arm-none-eabi
       if: (branch = staging OR branch = trying) OR (type = pull_request AND branch = master)
 
     - env: TARGET=thumbv7em-none-eabihf
       rust: nightly
-      addons:
-        apt:
-          packages:
-            - gcc-arm-none-eabi
       if: (branch = staging OR branch = trying) OR (type = pull_request AND branch = master)
 
 before_install: set -e