Fix missing esm file in the build output (#7)

* fix: remove type module option from package.json, fixes #6

This option also changes the outputs of tsup. So it does not output
index.mjs file but instead index.js and index.cjs files. This breaks esm
imports

* chore: set tsup version to ^8 to prevent future issues

* chore: change tsup config for consistency with other packages

package.json

@@ -4,7 +4,6 @@
   "main": "./dist/index.js",
   "module": "./dist/index.mjs",
   "types": "./dist/index.d.ts",
-  "type": "module",
   "scripts": {
     "test": "bun test",
     "fmt": "prettier --write .",
@@ -45,7 +44,7 @@
     "eslint-plugin-unicorn": "^51.0.1",
     "husky": "^9.0.10",
     "prettier": "^3.2.5",
-    "tsup": "latest",
+    "tsup": "^8.2.3",
     "typescript": "^5.4.5",
     "vitest": "latest"
   },

tsup.config.ts

@@ -1,10 +1,8 @@
 import { defineConfig } from "tsup";
 
 export default defineConfig({
-  entry: ["./index.ts"],
+  entry: ["index.ts"],
   format: ["cjs", "esm"],
-  sourcemap: false,
   clean: true,
   dts: true,
-  minify: true,
 });