Proposal to add Sambhav Kothari as a maintainer

[tomkennedy513]

• Non-trivial code changes - https://github.com/buildpacks-community/kpack/commits?author=samj1912
• Reviews - https://github.com/buildpacks-community/kpack/pulls?q=is%3Apr+sort%3Aupdated-desc+reviewed-by%3Asamj1912+
• Highlights:
  • Contributed support for project descriptor 0.1 and 0.2
  • Added support for platform api 0.6, 0.7 and 0.8
  • Helped improve the mixin validation to allow for wildcard stacks
  • Added support for publishing additional tags in the image/build resource
  • Fixed various resource/scaling issues by adding resource limits/priority classes
  • Helped review various pieces of supply chain security decisions around cosign integration
  • Various other minor bug fixes/CI/CD improvements
• Community engagement:
  • Helping draft the kpack donation proposal guidelines to allow kpack to be accepted into the buildpacks community org and suggesting improvements to be made to the project at https://docs.google.com/document/d/1LXj5_TSX1u2L88w5AD31bUl4lMQrqDO3-81cVEvPpKw/edit?pli=1#
  • Presented kpack during various talks including kubecon and packaging con

[chenbh]

lgtm

[tomkennedy513]

Since @chenbh and I have approved this (and @samj1912 has approved to confirm taking on the role), I am going to merge this PR. We are very excited to have you join the maintainers!