migrate to doc_auto_cfg

.github/workflows/upload-doc.yml

@@ -3,8 +3,7 @@ name: Upload Documentation
 on:
   push: { branches: [master] }
 
-permissions:
-  contents: read # to fetch code (actions/checkout)
+permissions: { contents: write }
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}
@@ -17,10 +16,9 @@ jobs:
     steps:
       - uses: actions/checkout@v3
 
-      - name: Install Rust
-        run: |
-          rustup override set nightly
-          rustup update nightly
+      - name: Install Rust (nightly)
+        uses: actions-rust-lang/setup-rust-toolchain@v1
+        with: { toolchain: nightly }
 
       - name: Build Docs
         run: cargo doc --workspace --all-features --no-deps