fix(package): correct main path

Use `/` instead of `.` (which likely was a typo) where a path needed to be separated.

Author: jdbruijn

package.json

@@ -2,7 +2,7 @@
   "name": "commitlint-plugin-function-rules",
   "version": "1.1.5",
   "description": "commitlint plugin to define rules as functions.",
-  "main": "dist/src.index.js",
+  "main": "dist/src/index.js",
   "types": "dist/src/index.d.js",
   "files": [
     "dist/src/**/!(*.test).{js,d.ts}"