feat: build & publish Docs to Github pages in CI

.github/workflows/ci-docs.yml

@@ -0,0 +1,40 @@
+name: Docs
+
+on:
+  push:
+    branches:
+      - master
+    paths:
+      - "**.rs"
+      - "Cargo.toml"
+      - "Cargo.lock"
+  workflow_dispatch:
+
+jobs:
+  docs:
+    name: Generate crate documentation
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@v2
+
+      - name: Install Rust toolchain
+        uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: nightly
+          override: true
+
+      - name: Generate documentation
+        uses: actions-rs/cargo@v1
+        env:
+          RUSTDOCFLAGS: "--enable-index-page -Zunstable-options"
+        with:
+          command: doc
+          args: --workspace --no-deps
+
+      - name: Deploy documentation
+        uses: peaceiris/actions-gh-pages@v3
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          publish_dir: ./target/doc