Please add your migration guide entries here. Until 3.0 is released, each PR
that makes backwards-incompatible changes should add a file here, with the
extension .md, a descriptive name and the following format:

---%<------%<------%<------%<------%<------%<------%<------%<---

The Change That Was Made
------------------------

Who exactly is affected: does this affect users of the default config, of a
particular feature? Remember to contextualise.

If I'm affected, what's my migration path? How should I change my code if this
is and API change; if a feature was removed what are my alternatives?

Optional: Another Change That Was Made in the Same Pr
-----------------------------------------------------

Who is affected?

What's the migration path?

---%<------%<------%<------%<------%<------%<------%<------%<---

For examples, have a look a docs/3.0-migration-guide.md (which includes the
top-level header and an intro before the list of entries).

As part of release preparation, the entries in this directory will be appended
to docs/3.0-migration-guide.md and then re-ordered and reviewed one last time.
The file is then going to be moved to the version-independant docs repo.