[Prettier Plugin] Bump major version to respect SemVer

[designorant]

I appreciate the docs mention the breaking change, and there is a upgrade guide but bumping minor versions shouldn't really warrant any of it given the SemVer-like versioning.

I understand many consider the plugin not v1 ready, but it's really just a number just like the minor/patch numbers.

I therefore propose that v0.5+ is bumped to v1.0+ to satisfy SemVer.

[designorant]

Reasoning: tailwindlabs/prettier-plugin-tailwindcss#207 (comment)