feat(npm): nocss package entry point

nocss/package.json

@@ -0,0 +1,6 @@
+{
+  "internal": true,
+  "main": "../dist/nocss/ReactFlow-nocss.js",
+  "module": "../dist/nocss/ReactFlow-nocss.esm.js",
+  "types": "../dist/nocss/index.d.ts"
+}

package.json

@@ -80,6 +80,7 @@
     "react": "16 || 17"
   },
   "files": [
-    "dist"
+    "dist",
+    "nocss"
   ]
 }