Update free-courses-hi.md (#8559)

* Update free-courses-hi.md

Added a Angular tutorial in Hindi.

* Update courses/free-courses-hi.md

* alphabetize

Co-authored-by: Eric Hellman <eric@hellman.net>

courses/free-courses-hi.md

@@ -88,6 +88,7 @@
 
 * [Angular 12 - 13 tutorial in Hindi](https://www.youtube.com/playlist?list=PL8p2I9GklV45--5t7_N4lveUI6Y31vQ6C) - Code Step By Step
 * [Angular 13 Tutorial in Hindi](https://www.youtube.com/playlist?list=PL_qizAfcpJ-N2mRgfQxnDgsv20daqwlfN) - Sahosoft Solutions
+* [Angular 6/7/8 Series (In Hindi)](https://www.youtube.com/playlist?list=PLLhsXdvz0qjL1HVD2jAtlvoDmS5qj0OvA) - UX Trendz
 * [Learn Angular in one video (Hindi)](https://www.youtube.com/watch?v=0LhBvp8qpro&list=PLu0W_9lII9ahKZ42vg2w9ERPmShYbYAB7&index=21) - Code With Harry