Update posthtml version in peerDependencies

[shoonia]

Hey!

Thank you for this amazing package. May you please update the version of PostHTML in peerDependencies.

I'm use:

node: v16.2.0
npm: 7.13.0

When I try to install this package with PostHTML v0.16.5 then I see the error:

npm ERR! Found: [email protected]
npm ERR! node_modules/posthtml
npm ERR!   dev posthtml@"^0.16.5" from the root project
npm ERR! 
npm ERR! Could not resolve dependency:
npm ERR! peer posthtml@"^0.12.0" from [email protected]
npm ERR! node_modules/posthtml-minify-classnames
npm ERR!   dev posthtml-minify-classnames@"^0.2.3" from the root project
npm ERR! 
npm ERR! Fix the upstream dependency conflict, or retry
npm ERR! this command with --force, or --legacy-peer-deps
npm ERR! to accept an incorrect (and potentially broken) dependency resolution.
npm ERR! 
npm ERR! See /Users/alexanderz/.npm/eresolve-report.txt for a full report.