fix: type exports in package.json

[qin-guan]

Types cannot resolve properly as it is not defined in exports field

Can be temporarily fixed using pnpm patch vue-cal

diff --git a/package.json b/package.json
index d720cc4f92df2d658d0ca64b831b58604d384549..ca053c36d1e3e40d35a03322ea6a81c03345cebf 100644
--- a/package.json
+++ b/package.json
@@ -20,7 +20,8 @@
   "exports": {
     ".": {
       "import": "./dist/vue-cal.es.js",
-      "require": "./dist/vue-cal.cjs.js"
+      "require": "./dist/vue-cal.cjs.js",
+      "types": "./dist/vue-cal.d.ts"
     },
     "./style": {
       "default": "./dist/vue-cal.css"