Use main instead of to dev/master

[philvarner]

Related Issue(s):

• update version references and migrate branches to use main instead of master/dev for rc.1 #259

Proposed Changes:

Change branch strategy to use main w/ tags instead of dev/master.

Former PR here: #268

There are two aspects to this change:

1. Changing from using a develop->released branch model to a single branch -- Until now, the dev branch was a rapidly-changing work-in-progress. It made sense to not make this the first thing people saw when they came to this repo. As we converge towards 1.0.0, there will be fewer significant changes in main that are not part of the latest released version. Most repos don't have master or a branch with their latest released version as the default branch, so users are used to main being the development tip.
2. Changing the name of the primary branch from master to main -- This has been a trend in the last couple years, motivated primarily by the origination and metaphorical use of the term "master" because of its use in the chattel slavery system in the United States prior to 1865. A project with a diverse audience should not use terms that are so blatantly offensive.

References:

• https://github.com/github/renaming
• Regarding Git and Branch Naming
• Why GitHub renamed its master branch to main

PR Checklist:

• This PR is made against the dev branch (all proposed changes except releases should be against dev, not master).
• This PR has no breaking changes.
• This PR does not make any changes to the core spec in the stac-spec directory (these are included as a subtree and should be updated directly in radiantearth/stac-spec)
• I have added my changes to the CHANGELOG or a CHANGELOG entry is not required.

[philvarner]

To address possible confusing about main being the development version, the top of the top-level README tools like this now:

[philvarner]

The second part of this that @cholmes brings up is that we should really convert this spec from intending to be a set of markdown docs in github to a generated website (e.g., like tools like Sphinx do).

[cholmes]

Looks good, added a suggestion to be more clear in the readme, to help non-developers understand what's going on. And like you mentioned I definitely think we should move towards a 'publish' step. The new stac website may offer some way to do it, but that's beyond my website & CI skills.

[philvarner]

I took a brief look at eleventy (the static site generator that's being used for stacspec.org) and was able to generate a site from the spec, though it didn't have any styling and most of the links were subtly wrong. But, I think it is feasible to use this to generate websites for stac-spec and stac-api-spec that we can publish, we just need to put a bit of work into it.