build: ensure types are defined in the exports in package.json

Author: axe312ger

package.json

@@ -7,7 +7,8 @@
   "exports": {
     ".": {
       "import": "./dist/esm/index.js",
-      "require": "./dist/contentful.cjs"
+      "require": "./dist/contentful.cjs",
+      "types": "./dist/types/index.d.ts"
     }
   },
   "browser": "./dist/contentful.browser.min.js",