set timeout on `yarn test` (#104)

It has been hanging on MacOS builds. Although we would want to fix this hang long term. This is a temporary way to deal with it and prevent future occurrences of swamping the CI. It would be surprising if jest tests ran longer than 15 minutes.

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

@@ -58,6 +58,7 @@ jobs:
       with:
         fetch-depth: 3
     - name: test
+      timeout-minutes: 15
       run: |
            cd ./cli/tauri.js
            yarn