Add missing entry point for generic typings (#284)

.changeset/fifty-mangos-know.md

@@ -0,0 +1,5 @@
+---
+"@saleor/app-sdk": patch
+---
+
+Added export path "@saleor/app-sdk/types". It was accessible but not correctly marked in package.json. Now its added in "exports" field which should fix some bundles and IDEs

package.json

@@ -134,6 +134,9 @@
       "types": "./headers.d.ts",
       "import": "./headers.mjs",
       "require": "./headers.js"
+    },
+    "./types": {
+      "types": "./types.d.ts"
     }
   },
   "publishConfig": {