Update testing workflow

.github/workflows/test.yml

@@ -2,13 +2,14 @@ name: Test Eel
 
 on:
   push:
-    branches: [ main ]
+    branches: [main]
   pull_request:
+    # The branches below must be a subset of the branches above
+    branches: [main]
+  workflow_dispatch:
 
 jobs:
   test:
-    runs-on: ${{ matrix.os }}
-
     strategy:
       fail-fast: false
       matrix:
@@ -18,6 +19,8 @@ jobs:
           - os: macos-latest
             python-version: 3.7
 
+    runs-on: ${{ matrix.os }}
+
     steps:
       - name: Checkout repository
         uses: actions/checkout@v2
@@ -31,15 +34,19 @@ jobs:
         run: tox -- --durations=0 --timeout=30
 
   typecheck:
-    runs-on: windows-latest
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest, macos-latest]
+
+    runs-on: ${{ matrix.os }}
 
     steps:
       - name: Checkout repository
         uses: actions/checkout@v2
       - name: Setup python
         uses: actions/setup-python@v2
         with:
-          python-version: "3.10"
+          python-version: "3.x"
       - name: Setup test execution environment.
         run: pip3 install -r requirements-meta.txt
       - name: Run tox tests