CHANGELOG: Fix GitHub and VMware casing

[stmcginnis]

Issue number:

N/A

Description of changes:

Trivial update to the change log. These are company names, so we should use their proper casing.

Testing done:

Visual inspection. Also ran grep of the rest of source to see if there were any other instances, but none found.

Terms of contribution:

By submitting this pull request, I agree that this contribution is dual-licensed under the terms of both the Apache License, version 2.0, and the MIT license.