Buttons > Review hover states

Button hover states seem to have a darker shadow than what appears in the Pajamas UI Kit. Correct button hover states to match the UI Kit. https://www.figma.com/file/qEddyqCrI7kPSBjGmwkZzQ/Pajamas-UI-Kit?node-id=2956%3A3038

GitLab UI is using .2 opacity while Pajamas UI Kit is using .08 opacity.