faster, cheaper (pick two): improve CI workflow and switch to free github runner (#5702)

Co-authored-by: Douwe Osinga <douwe@block.xyz>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

.github/workflows/pr-smoke-test.yml

@@ -55,33 +55,18 @@ jobs:
         with:
           ref: ${{ github.event.inputs.branch || github.ref }}
 
-      - name: Activate hermit and set CARGO_HOME
-        run: |
-          source bin/activate-hermit
-          echo "CARGO_HOME=$CARGO_HOME" >> $GITHUB_ENV
-          echo "RUSTUP_HOME=$RUSTUP_HOME" >> $GITHUB_ENV
+      - uses: actions-rust-lang/setup-rust-toolchain@v1
 
       - name: Install Dependencies
         run: |
           sudo apt update -y
           sudo apt install -y libdbus-1-dev gnome-keyring libxcb1-dev
 
-      - name: Cache Cargo artifacts
-        uses: actions/cache@2f8e54208210a422b2efd51efaa6bd6d7ca8920f # pin@v3
-        with:
-          path: |
-            ${{ env.CARGO_HOME }}/bin/
-            ${{ env.CARGO_HOME }}/registry/index/
-            ${{ env.CARGO_HOME }}/registry/cache/
-            ${{ env.CARGO_HOME }}/git/db/
-            target/
-          key: ${{ runner.os }}-cargo-release-${{ hashFiles('**/Cargo.lock') }}
-          restore-keys: |
-            ${{ runner.os }}-cargo-release-
+      - name: Cache Rust dependencies
+        uses: Swatinem/rust-cache@v2
 
       - name: Build Release Binary for Smoke Tests
         run: |
-          source ./bin/activate-hermit
           cargo build --release
 
       - name: Upload Binary for Smoke Tests