netlify-cms-app fails to install with react 17 as version 6 of react-aria-menubutton in incompatible with react 17

Describe the bug

When installing netlify-cms-app with react 17 the install fails with the following error:

npm ERR! code ERESOLVE
npm ERR! ERESOLVE unable to resolve dependency tree
npm ERR! 
npm ERR! Found: react@17.0.2
npm ERR! node_modules/react
npm ERR!   peer react@"17.0.2" from react-dom@17.0.2
npm ERR!   node_modules/react-dom
npm ERR!     react-dom@"^17.0.2" from the root project
npm ERR!     peer react-dom@"^16.8.4 || ^17.0.0" from netlify-cms-app@2.15.6
npm ERR!     node_modules/netlify-cms-app
npm ERR!       netlify-cms-app@"*" from the root project
npm ERR!     8 more (netlify-cms-widget-date, ...)
npm ERR!   react@"^17.0.2" from the root project
npm ERR!   38 more (netlify-cms-app, @emotion/core, @emotion/styled, ...)
npm ERR! 
npm ERR! Could not resolve dependency:
npm ERR! peer react@"0.14.x || ^15.0.0 || ^16.0.0" from react-aria-menubutton@6.3.0
npm ERR! node_modules/netlify-cms-ui-default/node_modules/react-aria-menubutton
npm ERR!   react-aria-menubutton@"^6.0.0" from netlify-cms-ui-default@2.13.1
npm ERR!   node_modules/netlify-cms-ui-default
npm ERR!     netlify-cms-ui-default@"^2.13.1" from netlify-cms-app@2.15.6
npm ERR!     node_modules/netlify-cms-app
npm ERR!       netlify-cms-app@"*" from the root project
npm ERR!     23 more (netlify-cms-backend-azure, ...)
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!

It seems like react-aria-menubutton in netlify-cms-ui-default needs to be upgraded to version 7.0.1 see: https://github.com/davidtheclark/react-aria-menubutton/issues/140

To Reproduce

Run npm init -y && npm i react react-dom && npm i netlify-cms-app in an empty directory. See Error

Expected behavior

netlify-cms-app installs without having to use --legacy-peer-deps

Screenshots

NA

Applicable Versions:

• Netlify CMS version: 2.15.6
• Git provider: NA
• OS: Arch Linux
• Browser version NA
• NPM version: 7.12.1
• Node.JS version: 16.1.0

CMS configuration

NA

Additional context

Seems like a dependency that didn’t get updated while fixing https://github.com/netlify/netlify-cms/issues/5111

[JeremyGrieshop]

Btw Jeremy let me know if the attribution I included in the commit looks good to you (I included the README and a link to your repository)

Looks great! I hope you find it useful and that I didn’t leave anything out of the original work.

[LuisOsta]

@erezrokah Sounds great! I’m working on that right now in this fork https://github.com/LuisOsta/netlify-cms based on the version created by @JeremyGrieshop.

Btw Jeremy let me know if the attribution I included in the commit looks good to you (I included the README and a link to your repository)