Please help beta-test the Trac -> GitHub transition guide

[Matthias Koeppe]

https://github.com/sagemath/sage/wiki/migration-from-trac-to-Git**b#proposed-workflow-on-github-with-transition-guide-from-trac

Writing this guide was motivated by 

- the proposed migration from Trac to GitHub (https://trac.sagemath.org/ticket/30363), 

but independent from that, the transition guide may also be useful for experienced Sage developers who are familiar with Trac but wish to start contributing to other projects, including:

(1) Projects on https://github.com/sagemath, including:

  - https://github.com/sagemath/sagetex

  - https://github.com/sagemath/pplpy

  - https://github.com/sagemath/sage-shell-mode

  - https://github.com/sagemath/cysignals

  - https://github.com/sagemath/modular_resolution

  - https://github.com/sagemath/deformation

  - https://github.com/sagemath/p_group_cohomology

  - https://github.com/sagemath/sage-combinat-widgets

(2) Our website:

  - https://github.com/sagemath/website

  - https://github.com/sagemath/publications

(3) External Sage user packages

  - see https://trac.sagemath.org/ticket/31164 for a collection -- the overwhelming majority is developed in GitHub repos; and many need help 

(4) Upstream packages (packages that Sage depends on)

  - see https://trac.sagemath.org/#Surveyingthemathematicalsoftwarelandscape

As an exercise for beta-testing the Trac -> GitHub transition guide that is accessible to everyone, I would suggest that we collaborate on updating ​https://github.com/sagemath/publications (add your own publications that cite Sage, fix open issues at ​https://github.com/sagemath/publications/issues). There is an opportunity for a first interaction with a ​GH Actions check that checks the wellformedness of the edited BibTeX entries.