Update Kotlin course for Thais (#8231)

* Update Kotlin course for Thais

* fix spacing and order

* spacing fix

* Update courses/free-courses-th.md

Co-authored-by: Sharan J <50091666+shrn01@users.noreply.github.com>

Co-authored-by: Eric Hellman <eric@hellman.net>
Co-authored-by: Sharan J <50091666+shrn01@users.noreply.github.com>

courses/free-courses-th.md

@@ -70,6 +70,11 @@
 * [สอน VueJS + NuxtJS ตั้งแต่ 0~99](https://www.youtube.com/playlist?list=PLXm-UJjVcJCMd24NIQTPcqHhfnK-QbPmD) - Geekstart
 
 
+### Kotlin
+
+* [Getting started with Kotlin](https://www.skooldio.com/courses/getting-started-with-kotlin) - Somkiat Kijwongwattana
+
+
 ### Python
 
 * [ชีวิตคนช่างแสนสั้น เราไม่หวั่นใช้ python](https://phyblas.hinaboshi.com/saraban/python) - Phyblas