Add basic github actions CI

Author: cmyr

.github/workflows/ci.yml

@@ -0,0 +1,58 @@
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+
+jobs:
+  rustfmt:
+    runs-on: macOS-latest
+    name: rustfmt
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: install stable toolchain
+        uses: actions-rs/toolchain@v1
+        with:
+          toolchain: stable
+          profile: minimal
+          components: rustfmt
+          override: true
+
+      - name: install rustfmt
+        run: rustup component add rustfmt
+
+      - name: cargo fmt
+        uses: actions-rs/cargo@v1
+        with:
+          command: fmt
+          args: --all -- --check
+
+  test-stable:
+    runs-on: macOS-latest
+    name: cargo test stable
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: install cairo
+        run: brew install cairo
+        if: contains(matrix.os, 'mac')
+
+      - name: install stable toolchain
+        uses: actions-rs/toolchain@v1
+        with:
+          toolchain: stable
+          components: clippy
+          profile: minimal
+          override: true
+
+      - name: cargo clippy
+        uses: actions-rs/cargo@v1
+        with:
+          command: clippy
+          args: -- -D warnings
+
+      - name: cargo test
+        uses: actions-rs/cargo@v1
+        with:
+          command: test