Add content for FVM (#3759)

* Adding content for FVM

* Update src/data/roadmaps/flutter/content/101-setup-development-environment/102-fvm.md

---------

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

src/data/roadmaps/flutter/content/101-setup-development-environment/102-fvm.md

@@ -1 +1,13 @@
 # FVM (Flutter Version Manager)
+
+Flutter version manager is a tool used to manage different versions of Flutter SDK on a developer's machine. Flutter is a popular open-source mobile application development framework, and its SDK is updated frequently with new features, bug fixes, and improvements. However, sometimes developers need to work with older versions of Flutter due to various reasons like compatibility issues or project requirements.
+
+Flutter version manager allows developers to easily switch between different versions of the Flutter SDK on their machine without having to uninstall or manually install each version. It provides a command-line interface (CLI) that enables developers to install, list, and switch between different Flutter SDK versions.
+
+Flutter version manager also allows developers to easily manage their Flutter channel, which determines the frequency of SDK updates they receive. For example, developers can switch between the stable, beta, or dev channel based on their preferences.
+
+Using Flutter version manager can help developers ensure that their project works with the desired version of Flutter SDK and minimize the time and effort required to manage multiple Flutter SDK versions.
+
+Here are some of the links
+
+- [Flutter Version Manager - Official Website](https://fvm.app/)