CI: test dev SDK with dart2wasm (dart-lang/web_socket_channel#304)

pkgs/web_socket_channel/.github/workflows/test-package.yml

diff --git a/pkgs/web_socket_channel/.github/workflows/test-package.yml b/pkgs/web_socket_channel/.github/workflows/test-package.yml
index bf51a79..e25fcf6 100644
--- a/pkgs/web_socket_channel/.github/workflows/test-package.yml
+++ b/pkgs/web_socket_channel/.github/workflows/test-package.yml
@@ -57,3 +57,6 @@
       - name: Run Chrome tests
         run: dart test --platform chrome
         if: always() && steps.install.outcome == 'success'
+      - name: Run Chrome tests - wasm
+        run: dart test --platform chrome --compiler dart2wasm
+        if: always() && steps.install.outcome == 'success' && matrix.sdk == 'dev'