add microbundle

Author: ReeceM

package.json

@@ -2,19 +2,26 @@
   "name": "@reecem/custom-type-api",
   "version": "0.1.1",
   "description": "API interface for the Prismic.io Custom Type API (beta)",
-  "main": "dist/index.js",
+  "type": "module",
+  "source": "src/index.ts",
+  "main": "./dist/index.cjs",
+  "module": "./dist/index.mjs",
   "scripts": {
     "test": "echo \"Error: no test specified\" && exit 1",
-    "build": "tsc --build tsconfig.json"
+    "build": "microbundle",
+    "dev": "microbundle watch",
+    "tsc-build": "tsc --build tsconfig.json"
   },
   "keywords": [
     "prismic.io",
-    "custom-type"
+    "custom-types",
+    "slices"
   ],
   "author": "ReeceM",
   "license": "ISC",
   "devDependencies": {
     "@types/node-fetch": "^2.5.10",
+    "microbundle": "^0.13.3",
     "typescript": "^4.2.4"
   },
   "dependencies": {