Try another URL for Rust setup

.forgejo/workflows/build.yaml

@@ -10,7 +10,7 @@ jobs:
       - name: Install Python dependencies
         run: pip install -r requirements.txt
       - name: Set up Rust
-        uses: dtolnay/rust-toolchain@stable
+        uses: https://github.com/actions-rust-lang/setup-rust-toolchain@v1
       - name: Install Rust dependencies
         run: cargo fetch
       - name: Check formatting