Quote the Rust toolchain version

Otherwise 1.70 is turned into 1.7.

.github/workflows/test.yml

@@ -71,7 +71,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@master
         with:
-          toolchain: 1.70
+          toolchain: "1.70"
       - uses: actions/cache@v4
         with:
           path: |