Fix upload to PyPI

Multiple things failed at once:
1. Link to readme was lost during conversion to `pyproject.toml` in f668317. This commit restores it.
2. PyPI only accepts rst/markdown/txt, so undo conversion of readme to AsciiDoc that was done in 55191a7
3. twine has a bug that prevents upload from working without readme: pypa/twine#908

Also run `twine check` on CI to detect `pyproject.toml` metadata errors earlier

.github/workflows/ci.yml

@@ -16,9 +16,11 @@ jobs:
       with:
         python-version: "3.10"
     - name: Install dependencies
-      run: pip install --upgrade build
+      run: pip install --upgrade build twine
     - name: Build package
       run: python -m build
+    - name: Check package
+      run: twine check --strict dist/*.whl
     - name: Publish to PyPI
       if: github.event_name == 'push' && startsWith(github.ref, 'refs/tags')
       uses: pypa/gh-action-pypi-publish@release/v1

README.md

@@ -0,0 +1,39 @@
+<p align="center"><img src="https://raw.githubusercontent.com/adamrehn/ue4-docker/master/resources/images/banner.svg?sanitize=true" alt="Unreal Engine and Docker Logos" height="100"></p>
+<h1 align="center"><strong>Unreal Engine 4 Docker Containers</strong></h1>
+<h3 align="center"><a href="https://docs.adamrehn.com/ue4-docker/use-cases/continuous-integration">Continuous Integration</a> &bull; <a href="https://docs.adamrehn.com/ue4-docker/use-cases/cloud-rendering">Cloud Rendering</a> &bull; <a href="https://docs.adamrehn.com/ue4-docker/use-cases/microservices">UE4-Powered Microservices</a></h3>
+<p>&nbsp;</p>
+
+**Looking for a place to start? Check out the [Unreal Containers community hub](https://unrealcontainers.com/) for implementation-agnostic information on using the Unreal Engine inside Docker containers, and then head to the [comprehensive ue4-docker documentation](https://docs.adamrehn.com/ue4-docker/) to view details specific to using the ue4-docker project.**
+
+The ue4-docker Python package contains a set of Dockerfiles and accompanying build infrastructure that allows you to build Docker images for Epic Games' [Unreal Engine 4](https://www.unrealengine.com/). The images also incorporate the infrastructure from [ue4cli](https://github.com/adamrehn/ue4cli), [conan-ue4cli](https://github.com/adamrehn/conan-ue4cli), and [ue4-ci-helpers](https://github.com/adamrehn/ue4-ci-helpers) to facilitate a wide variety of use cases.
+
+Key features include:
+
+- Unreal Engine 4.20.0 and newer is supported.
+- Both Windows containers and Linux containers are supported.
+- Building and packaging UE4 projects is supported.
+- Running automation tests is supported.
+- Running built UE4 projects with offscreen rendering is supported via NVIDIA Docker under Linux.
+
+Resources:
+
+- **Documentation:** <https://docs.adamrehn.com/ue4-docker/>
+- **GitHub repository:** <https://github.com/adamrehn/ue4-docker>
+- **Package on PyPI:** <https://pypi.org/project/ue4-docker/>
+- **Related articles:** <https://adamrehn.com/articles/tag/Unreal%20Engine/>
+- **Unreal Containers community hub:** <https://unrealcontainers.com/>
+- **Development channel on the Unreal Containers Community Discord server**: <https://discord.gg/46CJg9fyJ9>
+
+
+## Contributing
+
+See the file [CONTRIBUTING.md](https://github.com/adamrehn/ue4-docker/blob/master/CONTRIBUTING.md) for guidelines on how to contribute to the development of ue4-docker.
+
+
+## Legal
+
+Copyright &copy; 2018 - 2021, Adam Rehn. Licensed under the MIT License, see the file [LICENSE](https://github.com/adamrehn/ue4-docker/blob/master/LICENSE) for details.
+
+Unreal and its logo are Epic Games' trademarks or registered trademarks in the US and elsewhere.
+
+Docker and the Docker logo are trademarks or registered trademarks of Docker in the United States and other countries.

pyproject.toml

@@ -4,6 +4,7 @@ version = "0.0.104"
 description = "Windows and Linux containers for Unreal Engine"
 requires-python = ">= 3.7"
 license = { file = "LICENSE" }
+readme = "README.md"
 authors = [
     { name = "Adam Rehn", email = "adam@adamrehn.com" },
     { name = "Marat Radchenko", email = "marat@slonopotamus.org" },