Update rust.yml

.github/workflows/rust.yml

@@ -15,6 +15,10 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
+    - name : Install ARM compiler
+      run: sudo apt-get install gcc-arm-linux-gnueabihf -y
+    - name: Set ARM compiler as environment variable
+      run: export CC=arm-linux-gnueabihf-gcc
     - uses: actions-rs/toolchain@v1
       with:
         toolchain: stable