feat: ci caches rust deps b/wn builds (#7)

Author: phildenhoff

.github/workflows/build.yml

@@ -58,6 +58,14 @@ jobs:
         with:
           bun-version: latest
 
+      - run: rustup toolchain install stable --profile minimal
+
+      - uses: Swatinem/rust-cache@v2
+        with:
+          # using the default — we can bust the cache by changing this
+          prefix-key: "v0-rust"
+          workspaces: "src-tauri"
+
       - name: (Ubuntu only) Install dependencies
         if: matrix.platform == 'ubuntu-22.04'
         run: |