Remove sponsors

[rrrutledge]

• Create a checklist of things to do to remove a sponsor
• Review and sign off on the checklist
• Remove Indeed as a sponsor
• Remove Fannie Mae as a sponsor
• Remove Bitergia as a sponsor

Try them out on Adeo (now removed as a sponsor)

[rrrutledge]

See https://github.com/InnerSourceCommons/InnerSourceMarketing/blob/main/.github/ISSUE_TEMPLATE/add-a-new-sponsor.md

[rrrutledge]

• Indeed
• Fannie Mae

[rrrutledge]

• Bitergia

[Maryblessing]

I worked on a doc/checklist for removing a sponsor. @rrrutledge I remembered you had asked me to create this sometime in the past, so I'm sorry if we were waiting for that doc to get this done.

here it is for review: https://docs.google.com/document/d/1vWM7J6sFlUpLUJRoDqTwQzisUKd0a1cg-IItMorD9js/edit?usp=sharing