Set dtolnay toolchain to 1.85

Author: matze

.github/workflows/rust.yml

@@ -13,7 +13,7 @@ jobs:
     - name: Checkout repo
       uses: actions/checkout@v4
     - name: Install Rust
-      uses: dtolnay/rust-toolchain@stable
+      uses: dtolnay/rust-toolchain@1.85.0
       with:
         components: clippy
     - name: Run cargo-deny