Update requirements.txt

[tanujdhiman]

Issues in installing

Summary

Details

Checklist

• [ ] all tests are passing (see README.md on how to run tests)
• [ ] if you created a new template: it contains a file test-inputs.yml, which specifies a few input values to test the code template (the test is then automatically run by pytest)
• [ ] you formatted all code with black
• [ ] you checked all new functionality live, i.e. in the running web app
• [ ] any generated code is formatted nicely, both in .py and in .ipynb ("nicely" = comparable to the existing templates)
• [ ] you added comments in your code that explain what it does
• [x] the PR explains in detail what's new