Merge pull request #727 from rust-embedded/ci

run ci on merging instead of push

Author: Emilgardis

.github/bors.toml

@@ -1,7 +1,8 @@
 on:
   push:
-    branches: [ staging, trying, master ]
+    branches: master
   pull_request:
+  merge_group:
 
 name: Continuous integration
 
@@ -36,6 +37,9 @@ jobs:
         with:
           key: ${{ matrix.TARGET }}
 
+      - run: cargo check --target ${{ matrix.TARGET }}
+        env:
+          RUSTFLAGS: -D warnings
       - run: cargo clippy --target ${{ matrix.TARGET }}
 
   ci-linux: