Add Dependabot configuration file

[StoneMac65]

This pull request adds a configuration file for Dependabot, a tool that automatically scans the repository for outdated dependencies and security vulnerabilities. The configuration file (dependabot.yml) specifies settings such as the update frequency, package ecosystems to monitor, and dependencies to ignore.

Based on previous mentions and requests regarding security vulnerabilities on few third party dependencies it seems vital to add a mechanism to check and update needed changes.

https://github.com/anoma/namada/issues/2883

https://github.com/anoma/namada/issues/1023

Reason for Adding:

Automated Dependency Updates: Dependabot will help keep our project's dependencies up-to-date by automatically scanning for updates and opening pull requests to update them.
Enhanced Security: By regularly updating dependencies, we can mitigate security vulnerabilities and ensure that our project remains secure.
Reduced Maintenance Overhead: Dependabot automates the process of dependency management, reducing the manual effort required to monitor and update dependencies.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 53.88%. Comparing base (cc3edde) to head (7a1228a).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2913      +/-   ##
==========================================
- Coverage   53.88%   53.88%   -0.01%     
==========================================
  Files         308      308              
  Lines      100154   100154              
==========================================
- Hits        53967    53966       -1     
- Misses      46187    46188       +1     

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