Add python3 toolshed test

.github/workflows/toolshed.yaml

@@ -0,0 +1,25 @@
+name: Toolshed
+on: [push, pull_request]
+jobs:
+  test:
+    name: Test
+    runs-on: ubuntu-18.04
+    strategy:
+      matrix:
+        python-version: [3.7]
+    steps:
+    - uses: actions/checkout@v2
+      with:
+        path: 'galaxy root'
+    - uses: actions/setup-python@v1
+      with:
+        python-version: ${{ matrix.python-version }}
+    - name: Cache pip dir
+      uses: actions/cache@v1
+      id: pip-cache
+      with:
+        path: ~/.cache/pip
+        key: pip-cache-${{ matrix.python-version }}-${{ hashFiles('galaxy root/requirements.txt') }}
+    - name: Run tests
+      run: './run_tests.sh -toolshed'
+      working-directory: 'galaxy root'