Add module and typings properties

Update `main` key to point to the CJS variant.

Author: jessealama

package.json

@@ -1,7 +1,6 @@
 {
     "name": "decimal128",
     "version": "19.0.0",
-    "main": "src/Decimal128.js",
     "type": "module",
     "description": "Partial implementation of IEEE 754 Decimal128 decimal floating-point numbers",
     "directories": {
@@ -11,6 +10,9 @@
         "type": "git",
         "url": "https://github.com/jessealama/decimal128.js.git"
     },
+    "main": "dist/cjs/Decimal128.cjs",
+    "module": "dist/esm/Decimal128.mjs",
+    "typings": "dist/esm/Decimal128.d.ts",
     "sideEffects": false,
     "scripts": {
         "build": "rollup -c",