Create v0.11 Migration Guide branch

[dcroote]

TODO after v0.11 doc set is created.

The purpose is to create a migration guide branch that is added to during v0.11 development instead of going back through all issues and commits right before the release to try and figure out what changes could impact the user.

[wkande]

Good idea.

[wkande]

@dcroote - I just assumed you are doing this but let me know otherwise. I hopefully will have the v0.11 release of the docs ready Feb 7th.

[dcroote]

Yes I'll do it. Also you tagged someone that isn't me in your last comment 😅

[wkande]

@dcroote I just created the Airnode v0.11 doc set. In doing so I also made an adjustment to the migration.md doc, slight change to the how the <HEADINGs/> are presented.

[dcroote]

Closing as the draft / WIP PR branch is available here: https://github.com/api3dao/api3-docs/pull/1193