use ES modules

package.json

@@ -8,6 +8,7 @@
 		"dev": "npx rollup -c rollup.config.dev.js",
 		"build": "./build-extension.sh"
 	},
+	"type": "module",
 	"dependencies": {
 		"single-file-core": "1.5.15"
 	},

rollup.config.dev.js

@@ -1,7 +1,7 @@
 /* global require */
 
-const resolve = require("@rollup/plugin-node-resolve");
-const { terser } = require("rollup-plugin-terser");
+import resolve from "@rollup/plugin-node-resolve";
+import { terser } from "rollup-plugin-terser";
 
 const PLUGINS = [resolve({ moduleDirectories: [".."] })];
 const EXTERNAL = ["single-file-core"];

rollup.config.js

@@ -1,7 +1,7 @@
 /* global require */
 
-const resolve = require("@rollup/plugin-node-resolve");
-const { terser } = require("rollup-plugin-terser");
+import resolve from "@rollup/plugin-node-resolve";
+import { terser } from "rollup-plugin-terser";
 
 const PLUGINS = [resolve({ moduleDirectories: ["node_modules"] })];
 const EXTERNAL = ["single-file-core"];