flutter course update (#8481)

Co-authored-by: Ankit Singh <ankitsinghasingh007@gmail,com>

courses/free-courses-hi.md

@@ -206,6 +206,7 @@
 * [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
+* [Flutter Widgets in Hindi](https://www.youtube.com/playlist?list=PLz7ymP4HzwSH3vAnhDWLkO2TLbwGeigl7) - Ahirlog
 
 
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