fix: rename readme.md to README.md for npm package page

Author: AlexZeitler

readme.md README.mdreadme.md renamed to README.md

@@ -7,7 +7,7 @@
   "files": [
     "dist",
     "schema",
-    "readme.md",
+    "README.md",
     "LICENSE",
     "CHANGELOG.md"
   ],