feat(theme): Added zenburn theme

[FajarKim]

Description

Added zenburn theme. This theme inspired from https://github.com/phha/zenburn.nvim.

Type of change

• Bug fix (added a non-breaking change which fixes an issue)
• New feature (added a non-breaking change which adds functionality)
• Updated documentation (updated the readme, templates, or other repo files)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Misc change (updated other files non-breaking change)

How Has This Been Tested?

• Tested locally with a valid username
• Tested locally with an invalid username
• Ran tests with npm test
• Added or updated test cases to test new features

Checklist:

• I have checked to make sure no other pull requests are open for this issue
• The code is properly formatted and is consistent with the existing code style
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings

Screenshots

[vercel]

The latest updates on your projects. Learn more about Vercel for Git ↗︎

Name	Status	Preview	Updated (UTC)
github-readme-profile	✅ Ready (Inspect)	Visit Preview	Dec 1, 2023 2:54pm

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (ab2536f) 44.73% compared to head (7804f31) 44.73%.
Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #177   +/-   ##
=======================================
  Coverage   44.73%   44.73%           
=======================================
  Files          13       13           
  Lines         228      228           
  Branches       70       70           
=======================================
  Hits          102      102           
  Misses        109      109           
  Partials       17       17           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.