Publish announcement about Gin in core

xjm → credited catch → .

xjm → credited gábor hojtsy → .

xjm → credited griffynh → .

xjm → credited lauriii → .

xjm → credited pameeela → .

Crediting both the final announcment and an earlier draft.

xjm → credited jurgenhaas → .

xjm → credited saschaeggi → .

xjm → credited larowlan → .

xjm → credited longwave → .

xjm → credited poker10 → .

xjm → credited quietone → .

Also internal Slack discussion contributors. :)