Merge cranelift doc generation CI

cranelift/.github/workflows/main.yml

@@ -1,15 +0,0 @@
-jobs:
-  docs:
-    name: Build API Docs
-    runs-on: ubuntu-latest
-    steps:
-    - uses: actions/checkout@v1
-      with:
-        submodules: true
-    - name: Install Rust
-      run: rustup update nightly && rustup default nightly
-    - run: cargo doc --all --exclude cranelift-codegen-meta
-    - run: cargo doc --package cranelift-codegen-meta --document-private-items
-    - run: cargo install cargo-deadlinks
-    - run: find ./target/doc -maxdepth 1 -type d -name "cranelift*" | xargs -I{} cargo deadlinks --dir {}
-      name: Run cargo-deadlinks