Upgrade to postcss 7.x

[Olena-Stotska]

Could you please upgrade deps to use postcss 7.x?

Actually the better solution here would be moving postcss from dependencies to peerDependencies, as this library doesn't encapsulate postcss API, it's just a plugin. Also I'd recommend to enable https://renovatebot.com/ on github, it will make sure that your deps are always up to date

[stalniy]

I've just checked, all tests pass with postcss 7.x, so should be pretty easy to do

[stalniy]

I integrated renovate. The last thing you need to do is to enable it Settings > Integrations & services

[erredeco]

On my package.json I have:

"gulp-postcss": "^8.0.0",
 "postcss-sprites": "^4.2.1",

and I got the error:

Unknown error from PostCSS plugin. Your current PostCSS version is 7.0.6, but postcss-sprites uses 5.2.18. Perhaps this is the source of the error below
[...]
Stack:
TypeError: postcss.decl is not a function

Is this error related?