[Docs] Replace image in README file

[Atinuke Oluwabamikemi Kayode]

Current #State:
See the white background between the man and woman in the image below that needs to be updated to a better version in the README file.

Desired State:
This is the desired image.

Replace with the image below.

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Contributor Resources

• Meshery documentation site
• Meshery documentation source
• Instructions for contributing to documentation

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[Namita Arya]

can I take this up?

[Atinuke Oluwabamikemi Kayode]

@namitaarya sure you can!

[Namita Arya]

Hey @iambami, That's the first time I tried to sign off a commit. Do let me know in case there's a problem.

[Lee Calcote]

Whoo-hoo, @namitaarya! Another PR down!