chore: upgrade rust-cache to v2

Author: cwhitak3r

.github/workflows/rust.yml

@@ -33,7 +33,7 @@ jobs:
 
       # https://github.com/Swatinem/rust-cache
       - name: Cache Rust stuff
-        uses: Swatinem/rust-cache@v1
+        uses: Swatinem/rust-cache@v2
 
       - name: Install latest nextest release
         uses: taiki-e/install-action@nextest