Update rust.yml

you are getting to watch a perma-noob learn about CI in real time, this is special

.github/workflows/rust.yml

@@ -16,7 +16,8 @@ jobs:
 
     steps:
     - uses: actions/checkout@v2
+    - uses: textbook/git-checkout-submodule-action@master
     - name: Build
-      run: git submodule update --init && cargo build --verbose
+      run: cargo build --verbose
     - name: Run tests
-      run: git submodule update --init && cargo test --verbose
+      run: cargo test --verbose