feat: usage of ESM imports instead of CJS

BREAKING CHANGE: Require Node.js >= 12

close #27

index.js

@@ -1,7 +1,7 @@
-const stripIndent = require('strip-indent')
-const sass = require('sass')
+import stripIndent from 'strip-indent'
+import sass from 'sass'
 
-module.exports = (css, settings) => {
+export default (css, settings) => {
   const cssWithPlaceholders = css
     .replace(
       /%%styled-jsx-placeholder-(\d+)%%%(\w*\s*[),;!{])/g,

package.json

@@ -3,6 +3,7 @@
   "version": "3.0.0",
   "description": "Plugin to add Sass support to styled-jsx",
   "license": "MIT",
+  "type": "module",
   "main": "index.js",
   "engines": {
     "node": ">=12.0.0"
@@ -65,7 +66,7 @@
     "postpublish": "pinst --enable"
   },
   "dependencies": {
-    "strip-indent": "3.0.0"
+    "strip-indent": "4.0.0"
   },
   "devDependencies": {
     "@commitlint/cli": "12.1.4",

test.js

@@ -1,8 +1,8 @@
-const assert = require('assert')
-const path = require('path')
-const fs = require('fs')
-const stripIndent = require('strip-indent')
-const plugin = require('./')
+import assert from 'node:assert'
+import fs from 'node:fs'
+
+import stripIndent from 'strip-indent'
+import plugin from './index.js'
 
 const cleanup = (str) => stripIndent(str).trim()
 
@@ -143,7 +143,7 @@ describe('styled-jsx-plugin-sass', () => {
 
   it('works with relative @import', () => {
     const filename = 'fixtures/entry.scss'
-    const file = fs.readFileSync(path.join(__dirname, filename))
+    const file = fs.readFileSync(filename)
 
     assert.strictEqual(
       plugin(file.toString(), { babel: { filename } }).trim(),