Announcing release v2.9.1 of Oppia!

[Nithesh Hariharan]

Hi all,

    We are happy to announce the release of v2.9.1 of Oppia.
    The main changes in this release are a fix for a recurring server error, adding frontend tests for some services, adding audio duration to exploration schema, a lot of quality of life updates to learner and creator pages, infrastructural changes, and directory restructures within the codebase.

    Please welcome Florin Balint, Samriddhi Mishra, Scott Brenner, Shivansh Dhiman, Lakshay Angrish, and Safwan Mansuri for whom this release marks their first contribution to Oppia!

    Thanks to Abhay raghuwanshi, Abhith Krishna, Akshay Anand, Ankita Saxena, Anshul Hudda, Arnesh Agrawal, Brian Rodriguez, Brian Rodriguez, Harshit, Kevin Lee, Kevin Thomas, Mariana Zangrossi, Mohammad Zaman, Nishant Mittal, Nithesh N. Hariharan, Nitish Bansal, Prayush Dawda, RafayGhafoor, Rishabh Rawat, Rohit Katlaa, Sandeep Dubey, Sean Lip, Sudipta Gyan Prakash Pradhan, Tyler Ishikawa, U8N WXD, Varun Tandon, and Vojtěch Jelínek, our returning contributors who made this release possible.

    Finally, I'd like to thank Akshay, Divya, Chris, Rishabh, Kevin Thomas, Raina, Tejas for their help with pre-release testing, bug-fixing and QA, as well as Akshay for leading the QA team for this release.

Thanks,
Nithesh