Changes needed for new branch structure

[goneall]

From the 2024-08-14 tech discussion on spec publishing and the previous discussion on translations on 2024-06-11, we agreed to rename the "under development" branch to main. This will likely break the CI.

We should create a PR for CI updates, then rename the branch before merging.

We also need to document exactly what the changes are.

We also update README and/or CONTRIBUTING file

[goneall]

From the tech call on 5 November 2024, below are the specific changes we will make to the branches:

• Rename the currently under development branch "Development/v3.0.1" to "develop"
• Change default branch to develop
• For each branch under Development, create a branch under Support with exactly the same commit history of that Development branch with the name support/X.Y then delete the Development branch - e.g. create a support/2.3 with the same commit history as Development/v2.3 then delete the branch Development/v2.3 - Note this should be the same as renaming Development/v2.3 to support/2.3

@zvr @sbarnum - please review the above comment for accuracy

[bact]

With this setup, it will also be possible to publish new changes in "develop" immediately to a "staging" website; while keeping the "production" website to only be published from a tag in "main".

[bact]

Crossref similar issue in spdx-3-model repo:

• Update branching strategy for the 3.0.1 release spdx-3-model#903

[goneall]

Discussed on tech call 12 Nov 2024 - agreed to branch strategy

@bact will create a pull request to update the workflows
@goneall will merge the workflow updates and rename the branches