docs(index): add version command

Author: Lee-W

docs/index.md

@@ -1,4 +1,3 @@
-
 [![Github Actions](https://github.com/Woile/commitizen/workflows/Python%20package/badge.svg?style=flat-square)](https://github.com/Woile/commitizen/actions)
 [![Conventional
 Commits](https://img.shields.io/badge/Conventional%20Commits-1.0.0-yellow.svg?style=flat-square)](https://conventionalcommits.org)
@@ -8,7 +7,6 @@ release](https://img.shields.io/pypi/v/commitizen.svg?style=flat-square)](https:
 versions](https://img.shields.io/pypi/pyversions/commitizen.svg?style=flat-square)](https://pypi.org/project/commitizen/)
 [![Codecov](https://img.shields.io/codecov/c/github/Woile/commitizen.svg?style=flat-square)](https://codecov.io/gh/Woile/commitizen)
 
-
 ![Using commitizen cli](images/demo.gif)
 
 ## About
@@ -49,6 +47,7 @@ sudo pip3 install -U Commitizen
 ### Python project
 
 You can add it to your local project using one of these:
+
 ```bash
 pip install -U commitizen
 ```
@@ -61,14 +60,17 @@ poetry add commitizen --dev
 
 ### Commiting
 
-
 Run in your terminal
 
-    cz commit
+```bash
+cz commit
+```
 
 or the shortcut
 
-    cz c
+```bash
+cz c
+```
 
 ### Help
 
@@ -94,7 +96,10 @@ commands:
     info                show information about the cz
     schema              show commit schema
     bump                bump semantic version based on the git log
-    check               validates that a commit message matches the commitizen schema
+    version             get the version of the installed commitizen or the
+                        current project (default: installed commitizen)
+    check               validates that a commit message matches the commitizen
+                        schema
 ```
 
 ## Contributing