Add Github Actions workflow (#3)

.github/workflows/ci.yaml

@@ -0,0 +1,59 @@
+name: CI
+
+on: pull_request
+
+jobs:
+  fmt:
+    name: Rustfmt
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: stable
+          components: rustfmt
+      - uses: actions-rs/cargo@v1
+        with:
+          command: fmt
+          args: --all -- --check
+  clippy:
+    name: Clippy
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: stable
+          components: clippy
+      - uses: actions-rs/cargo@v1
+        with:
+          command: clippy
+          args: --all-features -- -D warnings
+  build_and_test:
+    name: Build and test
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: stable
+          target: thumbv6m-none-eabi
+      - name: Build
+        uses: actions-rs/cargo@v1
+        with:
+          command: build
+          args: --release --all-features
+      - name: Build example
+        uses: actions-rs/cargo@v1
+        with:
+          command: build
+          args: --release --example stm32f042 --target thumbv6m-none-eabi
+          use-cross: true
+      - name: Test
+        uses: actions-rs/cargo@v1
+        with:
+          command: test
+          args: --lib