Social Menu: Update Medium Icon

[Aurorum]

Changes proposed in this Pull Request:

• The current Medium icon used is outdated, it was changed in 2017. This PR proposes updating it.

Is this a new feature or does it add/remove features to an existing part of Jetpack?

• N/A

Testing instructions:

• Create a social menu with Medium as an icon and compare the two.

Before:

After:

Proposed changelog entry for your changes:

• Social menu: replace the outdated Medium icon with the new official design.

[jetpackbot]

	Warnings
⚠️	The PR is missing at least one [Status] label. Suggestions: [Status] In Progress, [Status] Needs Review

This is an automated check which relies on PULL_REQUEST_TEMPLATE. We encourage you to follow that template as it helps Jetpack maintainers do their job. If you think 'Testing instructions' or 'Proposed changelog entry' are not needed for your PR - please explain why you think so. Thanks for cooperation 🤖

Generated by 🚫 dangerJS against 179b480

[jeherve]

This works well for me. 👍

Matching PR to update the Medium icon elsewhere in Jetpack:
Automattic/social-logos#71

Noting that Genericons do not include the Medium icon, so to see this result one has to declare support for Social Menu with the SVG option:

add_theme_support( 'jetpack-social-menu', 'svg' );

Full documentation: https://jetpack.com/support/social-menu/

[jeherve]

Matching WordPress.com changes: D31683-code

[dereksmart]

Thank you!