Replace README.txt with README.md

Created MR for the issue.
Please review.
Thanks

Issue with the patch.

git.drupalcode.org_project_paystack_donate_-_merge_requests_1.patch.txt:22: trailing whitespace.
Users fill in their email, amount, and that's all. This uses the Paystack
git.drupalcode.org_project_paystack_donate_-_merge_requests_1.patch.txt:59: trailing whitespace.
*Note:* The donate link is also configurable. Do not forget to flush your cache
error: patch failed: README.txt:1
error: README.txt: patch does not apply

Hi Sonal Gyanani

I applied and reviewed your MR and confirmed that it replaced README.txt with README.md, but it doesn't follow README.md template → and has a missing information for maintainer. Please see the screenshots attached.

Thank you.

Anjali Mehta → made their first commit to this issue’s fork.

Changes to the readme.md file. Kindly review the changes.

Reviewed MR!1, the patch is not cleanly applied.

git.drupalcode.org_project_paystack_donate_-_merge_requests_1.diff.txt:10: trailing whitespace.
Users fill in their email, amount, and that's all. This module utilizes the
git.drupalcode.org_project_paystack_donate_-_merge_requests_1.diff.txt:11: trailing whitespace.
[Paystack inline API](https://paystack.com/docs/) allowing donations to be
git.drupalcode.org_project_paystack_donate_-_merge_requests_1.diff.txt:14: trailing whitespace.
- For a full description of the module, please visit the
git.drupalcode.org_project_paystack_donate_-_merge_requests_1.diff.txt:17: trailing whitespace.
- To submit bug reports, feature suggestions, or track changes, visit the
git.drupalcode.org_project_paystack_donate_-_merge_requests_1.diff.txt:36: trailing whitespace.
Install the Paystack Donate module as you would normally install a contributed Drupal module. For further information, visit
error: patch failed: README.txt:1
error: README.txt: patch does not apply

Hence unable to verify the readme.md file format as patch is not applied.

Reviewed MR!1, the patch is not cleanly applied.
1. "## Contents" should changed to "## Table of contents".
Please update readme.md file as per readme.md file template. Please refer https://www.drupal.org/docs/develop/managing-a-drupalorg-theme-module-or... →

I missed that, sorry. Fixed in latest commit. Please re-review the MR. Kind regards

Reviewed MR!1, the file is updated as per the readme.md file template. Hence marking it to RTBC.