Try to use GitHub releases to sync deployment of MacOS.

The previous tag method has failed since it didn't use the existing tag
but the previous one.  I need to look into this more.

.github/workflows/python-package-macos.yml

@@ -1,6 +1,11 @@
 name: Python package (MacOS)
 
-on: [push, pull_request]
+on:
+  push:
+  pull_request:
+  release:
+    types:
+      - created
 
 jobs:
   build:
@@ -18,6 +23,9 @@ jobs:
     - name: Checkout submodules
       run: |
         git submodule update --init --recursive --depth 1
+    - name: Print git describe
+      run: |
+        git describe
     - name: Set up Mac Python ${{ matrix.python-version }}
       # actions/setup-python can't be used as it builds less portable extensions.
       env:
@@ -37,6 +45,8 @@ jobs:
         python -m pip install pytest pytest-cov pytest-benchmark delocate wheel twine
         if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
     - name: Build package.
+      env:
+        TCOD_TAG: ${{ github.event.release.tag_name }}
       run: |
         python setup.py sdist develop bdist_wheel --py-limited-api=cp35
     - name: Package binary files
@@ -48,7 +58,7 @@ jobs:
         pytest --no-window --cov-report=xml
     - uses: codecov/codecov-action@v1
     - name: Upload to PyPI
-      if: startsWith(github.ref, 'refs/tags/')  # Only run on tags.
+      if: github.event_name == 'release'
       env:
         TWINE_USERNAME: ${{ secrets.PYPI_USERNAME }}
         TWINE_PASSWORD: ${{ secrets.PYPI_PASSWORD }}

setup.py

@@ -1,7 +1,7 @@
 #!/usr/bin/env python3
 
 import sys
-import os.path
+import os
 
 from setuptools import setup
 
@@ -14,6 +14,8 @@
 
 def get_version():
     """Get the current version from a git tag, or by reading tcod/version.py"""
+    if os.environ.get("TCOD_TAG"):
+        return os.environ["TCOD_TAG"]
     try:
         tag = check_output(
             ["git", "describe", "--abbrev=0"], universal_newlines=True