Ensure aarch64-apple-darwin can be built (#170)

* Ensure aarch64-apple-darwin can be built

* Remove unneeded xcode workaround

.github/workflows/rust-ci.yml

@@ -46,6 +46,22 @@ jobs:
         run: cargo build --tests --release
       - name: cargo test
         run: cargo test --release
+
+  build-aarch64-apple-darwin:
+    name: Build aarch64-apple-darwin
+    strategy:
+      matrix:
+        os: [macOS-latest]
+    runs-on: ${{ matrix.os }}
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions-rs/toolchain@v1
+        with:
+          toolchain: stable
+          override: true
+      - run: rustup target add aarch64-apple-darwin
+      - run: cargo fetch --target aarch64-apple-darwin
+      - run: cargo build --release --target aarch64-apple-darwin
 
   deny-check:
     name: cargo-deny
@@ -118,12 +134,6 @@ jobs:
         if: matrix.os == 'ubuntu-20.04'
         run: |
           sudo apt-get install -y musl-tools
-      - name: Workaround xcode shenanigans
-        if: matrix.target == 'aarch64-apple-darwin'
-        # https://github.com/actions/virtual-environments/issues/2557#issuecomment-769611326
-        run: |
-          sudo xcode-select -s "/Applications/Xcode_12.3.app"
-          sudo rm -Rf /Library/Developer/CommandLineTools/SDKs/*
       - name: Checkout
         uses: actions/checkout@v2
       - name: cargo fetch