flutter added (#8178)

courses/free-courses-hi.md

@@ -189,6 +189,7 @@
 * [Flutter 3 tutorial in Hindi](https://youtube.com/playlist?list=PLB97yPrFwo5g-XcPlfSXSOeeby23jVAcp) - CODERS NEVER QUIT
 * [Flutter Essential Course](https://www.youtube.com/watch?v=Wdx8vwN_nWI) - freecodecamp (YouTube)
 * [Flutter Series 2020](https://www.youtube.com/playlist?list=PLDzeHZWIZsTo3Cs115GXkot28i406511Y) - CodeHelp - by Babbar (YouTube)
+* [Flutter Tutorial for Beginners](https://www.youtube.com/playlist?list=PL4cUxeGkcC9jLYyp2Aoh6hcWuxFDX6PBJ) - The Net Ninja
 * [Flutter Tutorial For Beginners in Hindi](https://youtube.com/playlist?list=PLMkkZSS5OjPIwDyHHKVex6zr008U1-sWM) - Geeks Rank