Move postcss to deepDependencies

lib/autoprefixer.js

@@ -1,7 +1,6 @@
 let browserslist = require('browserslist')
+let { agents } = require('caniuse-lite')
 let colorette = require('colorette')
-let postcss = require('postcss')
-let agents = require('caniuse-lite').agents
 
 let Browsers = require('./browsers')
 let Prefixes = require('./prefixes')

lib/supports.js

@@ -1,13 +1,14 @@
-let postcss = require('postcss')
-let data = require('caniuse-lite').feature(
-  require('caniuse-lite/data/features/css-featurequeries.js')
-)
+let featureQueries = require('caniuse-lite/data/features/css-featurequeries.js')
+let { feature } = require('caniuse-lite')
+let { parse } = require('postcss')
 
 let Browsers = require('./browsers')
 let brackets = require('./brackets')
 let Value = require('./value')
 let utils = require('./utils')
 
+let data = feature(featureQueries)
+
 let supported = []
 for (let browser in data.stats) {
   let versions = data.stats[browser]
@@ -66,7 +67,7 @@ class Supports {
    */
   virtual (str) {
     let [prop, value] = this.parse(str)
-    let rule = postcss.parse('a{}').first
+    let rule = parse('a{}').first
     rule.append({ prop, value, raws: { before: '' } })
     return rule
   }

lib/utils.js

@@ -1,4 +1,4 @@
-let list = require('postcss').list
+let { list } = require('postcss')
 
 module.exports = {
   /**

package.json

@@ -25,13 +25,15 @@
   "author": "Andrey Sitnik <[email protected]>",
   "license": "MIT",
   "repository": "postcss/autoprefixer",
+  "peerDependencies": {
+    "postcss": "postcss/postcss#ose"
+  },
   "dependencies": {
     "browserslist": "^4.14.1",
     "caniuse-lite": "^1.0.30001124",
     "colorette": "^1.2.1",
     "normalize-range": "^0.1.2",
     "num2fraction": "^1.2.2",
-    "postcss": "postcss/postcss#ose",
     "postcss-value-parser": "^4.1.0"
   },
   "browser": {
@@ -58,6 +60,7 @@
     "jest": "^26.4.2",
     "jest-ci": "^0.1.1",
     "lint-staged": "^10.3.0",
+    "postcss": "postcss/postcss#ose",
     "size-limit": "^4.5.7"
   },
   "lint-staged": {