message: Use `nightly` toolchain in `document` CI workflow
diff: @@ -10,9 +10,12 @@ jobs:
  group: ${{ github.workflow }}-${{ github.ref }}
  steps:
  - uses: hecrj/setup-rust-action@v1
  + with:
  + rust-version: nightly
  - uses: actions/checkout@v2
  - name: Generate documentation
  run: |
  + RUSTDOCFLAGS="--cfg docsrs" \
  cargo doc --no-deps --all-features \
  -p iced_core \
  -p iced_style \
  