Run "tox -e pyinstaller" in a separate step

.github/workflows/ci.yml

@@ -65,9 +65,6 @@ jobs:
       - name: Run "tox -e coverage"
         run: tox -e coverage
 
-      - name: Run "tox -e pyinstaller"
-        run: tox -e pyinstaller
-
       - name: Upload eliot.log in case of failure
         uses: actions/upload-artifact@v1
         if: failure()
@@ -144,3 +141,47 @@ jobs:
           name: eliot.log
           path: eliot.log
 
+  packaging:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os:
+          - macos-latest
+          - windows-latest
+          - ubuntu-latest
+        python-version:
+          - 2.7
+
+    steps:
+
+      # Get vcpython27 on Windows + Python 2.7, to build zfec
+      # extension.  See https://chocolatey.org/packages/vcpython27 and
+      # https://github.com/crazy-max/ghaction-chocolatey
+      - name: [Windows] Install MSVC 9.0 for Python 2.7
+        if: matrix.os == 'windows-latest' && matrix.python-version == '2.7'
+        uses: crazy-max/ghaction-chocolatey@v1
+        with:
+          args: install vcpython27
+
+      - name: Check out Tahoe-LAFS sources
+        uses: actions/checkout@v2
+
+      - name: Fetch all history for all tags and branches
+        run: git fetch --prune --unshallow
+
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v1
+        with:
+          python-version: ${{ matrix.python-version }}
+
+      - name: Install Python packages
+        run: |
+          pip install --upgrade codecov tox setuptools
+          pip list
+
+      - name: Display tool versions
+        run: python misc/build_helpers/show-tool-versions.py
+
+      - name: Run "tox -e pyinstaller"
+        run: tox -e pyinstaller