add karthick3018 as a contributor for code

[allcontributors]

Adds @karthick3018 as a contributor for code.

This was requested by manojVivek in this comment

[skip ci]

[alwaysmeticulous]

✅ Meticulous spotted zero visual differences across 254 screens tested: view results.

_{Last updated for commit ae49d1c. This comment will update as new commits are pushed.}