Add content for Go interfaces (#1939)

* content for Go maps

* content for Golang's make function

* content for Golang structs

* Update content/roadmaps/109-golang/content/100-go-basics/116-structs.md

* content for Go interfaces

* Update content/roadmaps/109-golang/content/101-go-advanced/103-interfaces.md

Co-authored-by: Kamran Ahmed <kamranahmed.se@gmail.com>

content/roadmaps/109-golang/content/101-go-advanced/103-interfaces.md

@@ -1 +1,10 @@
-# Interfaces
+# Interfaces
+
+An interface in Go, is a type that defines a set of methods. If we have a type (e.g. struct) that implements that set of methods, then we have a type that implements this interface.
+
+<ResourceGroupTitle>Free Content</ResourceGroupTitle>
+
+<BadgeLink colorScheme='blue' badgeText='Official Website' href='https://go.dev/tour/methods/9'>Go Interfaces</BadgeLink>
+<BadgeLink badgeText='Read' href='https://gobyexample.com/interfaces'>Go by Example: Interfaces</BadgeLink>
+<BadgeLink badgeText='Watch' href='https://www.youtube.com/watch?v=lh_Uv2imp14'>Golang Tutorial #22 - Interfaces (by Tech With Tim on YouTube)</BadgeLink>
+<BadgeLink badgeText='Watch' href='https://www.youtube.com/watch?v=KB3ysH8cupY'>Learn Go Interfaces</BadgeLink>