Create LICENSE.txt (#121)

<!-- ISSUE & PR TITLE SHOULD BE SAME-->
## Description
<!--Please include a brief description of the changes-->
Added a license file `license.txt` to the repository to address the
issue regarding the addition of the MIT License.

## Related Issues
<!--Cite any related issue(s) this pull request addresses. If none,
simply state “None”-->
- Closes #116

## Type of PR
<!-- Mention PR Type according to the issue in brackets below and check
the below box -->
- [ ] Documentation Update

## Screenshots / videos (if applicable)
<!--Attach any relevant screenshots or videos demonstrating the
changes-->
N/A

## Checklist
<!-- [X] - put a cross/X inside [] to check the box -->
- [X] I have gone through the [contributing
guide](https://github.com/Anjaliavv51/Retro)
- [X] I have updated my branch and synced it with project `main` branch
before making this PR
- [X] I have performed a self-review of my code
- [X] I have tested the changes thoroughly before submitting this pull
request.
- [X] I have provided relevant issue numbers, screenshots, and videos
after making the changes.
- [X] I have commented my code, particularly in hard-to-understand
areas.

## Additional context:
<!--Include any additional information or context that might be helpful
for reviewers.-->
This PR adds the MIT License to the repository as specified in the issue
#116.

LICENSE.txt

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2024 Lakshmi Pavananjali
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.