format fixed

Author: mkumar73

docs/installation.md

@@ -15,7 +15,7 @@ Note: Make sure you in the same directory where `setup.py` file resides.
 The package is available on PyPi. You can install it using the following command:
 
 ```bash
-pip install mambular
+pip install -U mambular
 ```
 
 PyPi link: [mambular](https://pypi.org/project/mambular/)