Fix CI: pin Rust 1.93.1 for edition 2024 support

Author: AnshulDesai

.github/workflows/ci.yml

@@ -17,7 +17,9 @@ jobs:
       - uses: actions/setup-python@v5
         with:
           python-version: ${{ matrix.python-version }}
-      - uses: dtolnay/rust-toolchain@stable
+      - uses: dtolnay/rust-toolchain@master
+        with:
+          toolchain: "1.93.1"
       - run: cargo install toq-cli
       - run: pip install -e ".[dev]"
       - run: python -m pytest tests/ -v