Add the correct os cache key

Author: LegNeato

.github/workflows/rust.yml

@@ -94,7 +94,7 @@ jobs:
       - name: Load Rust Cache
         uses: Swatinem/[email protected]
         with:
-          key: ${{ runner.os }}-${{ matrix.target }}-${{ matrix.cuda }}
+          key: ${{ matrix.os }}-${{ matrix.target }}-${{ matrix.cuda }}
 
       - name: Rustfmt
         if: contains(matrix.os, 'ubuntu')