Add an algorithm example for converting decimal to binary

[Gokul45-45]

Description:
In the Hacktoberfest repository, many programming language folders are available to add simple algorithm examples. This issue proposes adding a new example: converting a decimal number to its binary representation.
Proposed steps:

Choose a language folder (for example, python/, javascript/, etc.) and create a file decimal_to_binary..

Implement a function that takes an integer input and returns/prints its binary equivalent.

Add comments or a small usage example.

Update the README (if needed) to list this new algorithm.
Labels you may suggest: good first issue, algorithm, enhancement.