Clean up github workflow.

- Runs clippy
- Checks it builds on multiple OSes
- Checks stable and nightly
- Doesn't install GCC

Author: thejpster

.github/workflows/rust.yml

@@ -2,21 +2,43 @@ name: Build
 
 on: [push, pull_request]
 
+env:
+  CARGO_TERM_COLOR: always
+
 jobs:
   build:
-
-    runs-on: ubuntu-latest
-
+    continue-on-error: ${{ matrix.experimental || false }}
+    strategy:
+      matrix:
+        # All generated code should be running on stable now
+        rust: [nightly, stable]
+        include:
+          # Nightly is only for reference and allowed to fail
+          - rust: nightly
+            experimental: true
+        os:
+          - ubuntu-latest
+          - macOS-latest
+          - windows-latest
+    runs-on: ${{ matrix.os }}
     steps:
-    - name: Checkout
-      uses: actions/checkout@v1
-      with:
-        submodules: true
-    - name: Install GCC ARM
-      run: sudo apt-get update && sudo apt-get install -y gcc-arm-none-eabi
-    - name: Add Target
-      run: rustup target add thumbv6m-none-eabi
-    - name: Build
-      run: cargo build --verbose
-    - name: Build Release
-      run: cargo build --release --verbose
+      - name: Checkout
+        uses: actions/checkout@v2
+        with:
+          submodules: true
+      - name: Build
+        uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: ${{ matrix.rust }}
+          override: true
+      - name: Install Rust targets for ${{ matrix.rust }}
+        run: rustup target install --toolchain=${{ matrix.rust }} thumbv6m-none-eabi
+      - name: Build
+        run: cargo build --verbose
+      - name: Build Release
+        run: cargo build --release --verbose
+      - name: Clippy
+        uses: actions-rs/clippy-check@v1
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}