Migrate to GitHub actions

.github/workflows/fmt.yaml

@@ -0,0 +1,21 @@
+name: 'Check Formatting'
+on: [push]
+
+jobs:
+  check-fmt:
+    runs-on: ubuntu-20.04
+    steps:
+    - uses: actions/checkout@v1
+      with:
+        fetch-depth: 1
+        submodules: true
+    - name: Install Rust
+      run: |
+        rustup update stable
+        rustup default stable 
+        rustup component add rustfmt
+    - name: Generate missing bindings.rs file
+      run: |
+        echo > skia-bindings/src/bindings.rs
+    - run: | 
+        cargo fmt -- --check