Improve accessibility color contrast of BLM banner.

[karnett]

Describe the bug
The current blue against the background fails contrast guidelines at 2.59:1

AA compliance requires at least 4.5:1
Moving up the lightness scale recommends #6782DA, if you don't have something that fits within your color palette.
Thanks for all the work you do.

To Reproduce
Steps to reproduce the behavior:

1. Go to https://momentjs.com
2. Observe color of blue links against dark background.

Expected behavior
Links within the BLM banner should meet accessibility standard of 4.5:1 contrast.

Screenshots
Via: https://webaim.org/resources/contrastchecker/

Desktop (please complete the following information):

• OS: MacOS
• Browser: Safari
• Version 13.1.2

[marwahaha]

Hi @karnett ! Thanks for reporting this. This is an important thing to consider, so thanks for the webaim link also.

I took your suggestion on the color.

Cheers!