Enhancement: Remove border conflicts with backgrounds, update border vars

[bstifle]

Related issue: https://github.com/Esri/calcite-components/issues/2042

The following Sass variables need to be updated for theming in calcite-components. Since the light/dark theme mixins use these vars, I'm thinking we want to update them from the variables themselves (ie., update the vars so the Calcite CSS properties in each mixin pull the new values - Cari):

Sass var theme changes	OLD	NEW
Light theme
	$ui-border-2-light: #dfdfdf (blk-030)	#d4d4d4 (blk-040)
	$ui-border-3-light: #eaeaea (blk-020)	#dfdfdf (blk-030)
Dark theme
	$ui-border-1-dark: #4a4a4a (blk-170)	#555555 (blk-160)
	$ui-border-2-dark: #404040 (blk-180)	#4a4a4a (blk-170)
	$ui-border-3-dark: #353535 (blk-190)	#404040 (blk-180)

Mockups:

Light changes: border-1: NO CHANGE border-2: blk-040 border-3: blk-030

Dark changes: border-1: blk-160 border-2: blk-170 border-3: blk-180

[caripizza]

@paulcpederson is it okay if I open a pr for this one via my fork? Now that I'm viewing the previous work from the changelog, this change doesn't seem like it'd break anything, it's just updating a few of the theme Sass var hex values.

[paulcpederson]

go for gold 🥇 🍕

[caripizza]

pr #71 addresses this issue

[caripizza]

Installed. After chatting with Paul just now, we'll release this new version and plan to consume it in calcite-components after next week.

[caripizza]

@paulcpederson can you please cut a new calcite-colors release for this one when time permits?

[bstifle]

Thanks guys! I'll update figma now

[caripizza]

@driskull can you cut a new release of calcite-colors for this update?

[driskull]

@caripizza do you not have access to npm? Maybe we can get you access

[driskull]

https://github.com/Esri/calcite-colors/blob/master/CONTRIBUTE.md#releasing-a-version