Check no-std compatibility

.github/workflows/ci.yml

@@ -50,6 +50,27 @@ jobs:
           command: test
           args: --verbose --release
 
+  no-std:
+    name: Check no-std compatibility
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v1
+      - uses: actions-rs/toolchain@v1
+        with:
+          toolchain: 1.33.0
+          override: true
+      - run: rustup target add thumbv6m-none-eabi
+      - name: cargo fetch
+        uses: actions-rs/cargo@v1
+        with:
+          command: fetch
+      - name: Build
+        uses: actions-rs/cargo@v1
+        with:
+          command: build
+          args: --verbose --target thumbv6m-none-eabi --no-default-features
+
   doc-links:
     name: Nightly lint
     runs-on: ubuntu-latest