fix(ci): wasm tests (paritytech#720)

Author: niklasad1

.github/workflows/rust.yml

@@ -176,9 +176,15 @@ jobs:
     steps:
     - uses: actions/[email protected]
 
-    - name: Install
+    - name: Install wasm-pack
       run: curl https://rustwasm.github.io/wasm-pack/installer/init.sh -sSf | sh
 
+    - name: Install firefox
+      uses: browser-actions/setup-firefox@latest
+
+    - name: Install chrome
+      uses: browser-actions/setup-chrome@latest
+
     - name: Download Substrate
       run: |
         curl $SUBSTRATE_URL --output substrate --location