build(ci): add some simple CI for cargo {check,fmt,test}

.github/workflows/push.yml

@@ -0,0 +1,102 @@
+name: Push checks
+
+on: [push]
+
+jobs:
+  check:
+    name: Check
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest, macOS-latest]
+        rust:
+          - stable
+          - beta
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@v1
+
+      - name: Install toolchain
+        uses: actions-rs/toolchain@v1
+        with:
+          toolchain: ${{ matrix.rust }}
+          override: true
+
+      - name: "Run `cargo check`"
+        uses: actions-rs/cargo@v1
+        with:
+          command: check
+
+  test:
+    name: Test Suite
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest, macOS-latest]
+        rust:
+          - stable
+          - beta
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@v1
+
+      - name: Install toolchain
+        uses: actions-rs/toolchain@v1
+        with:
+          toolchain: ${{ matrix.rust }}
+          override: true
+
+      - name: "Run `cargo test`"
+        uses: actions-rs/cargo@v1
+        with:
+          command: test
+
+  fmt:
+    name: Rustfmt
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        rust:
+          - stable
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@v1
+
+      - name: Install toolchain
+        uses: actions-rs/toolchain@v1
+        with:
+          toolchain: ${{ matrix.rust }}
+          override: true
+          components: rustfmt
+
+      - name: "Run `cargo fmt`"
+        uses: actions-rs/cargo@v1
+        with:
+          command: fmt
+          args: --all -- --check
+
+  clippy:
+    name: Clippy
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest, macOS-latest]
+        rust:
+          - stable
+          - beta
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@v1
+
+      - name: Install toolchain
+        uses: actions-rs/toolchain@v1
+        with:
+          toolchain: ${{ matrix.rust }}
+          override: true
+          components: clippy
+
+      - name: "Run `cargo clippy`"
+        uses: actions-rs/cargo@v1
+        with:
+          command: clippy
+          args: -- -D warnings