Write section on how to contribute to PLFA

[wenkokke]

Suggested workflow:

1. Open an issue describing the proposed contribution;
2. Discuss proposal with existing contributors;
3. Create pull request for contribution;
4. Publish contribution with draft tag, which labels the chapters as “Under construction”;
5. Merge pull request, removing the draft tag;
6. Add contributor information to author list.

Technical questions:

• Can we automatically publish chapters from open pull requests labeled #new-content with a draft tag, but ensure that we don’t block updating the live version of the website if they fail to build?
• Can we automatically publish the website compiled from open pull requests to a version path?

[wenkokke]

Can we automatically publish the website compiled from open pull requests to a version path, provided they are labeled with new-chapter?

Could be done by running the github-pages-deploy-action for labeled pull requests which uses target-folder to deploy to, e.g., /PR/<pull_request_id>, and properly configuring all deploy actions using clean-exclude to not remove directories corresponding to open pull requests.

Another solution would be to have each build task upload an artefact, and create a separate deploy task which downloads all artefacts and publishes them! See the github-pages-deploy-action documentation.