adding solution for indorder traversal python

[sachinnegi]

Pull Request Template

Description

Please include a summary of the problem and about the approach to solve the solution. Please also include relevant motivation and context.
List any dependencies that are required for this change.

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Have you made changes in README file ?

• Added problem & solution under correct topic.
• Specified Space & Time complexity.
• Specified difficulty level, tag & Note(if any).

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Please also note any relevant details for your test configuration.

• Test A
• Test B

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• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code so that it is easy to understand
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• Any dependent changes have been merged and published in downstream modules

[sachinnegi]

@GouravRusiya30 I have created this new pr.