Adds what's new button to welcome

src/webviews/apps/welcome/index.html

@@ -77,6 +77,11 @@
 					<h2 class="section__title section__title--primary">
 						Welcome to <span class="highlight">GitLens 10</span>
 					</h2>
+					<div class="center mt-1">
+						<a class="button button--flat" title="See What's New" href="https://gitlens.amod.io/#whats-new"
+							>See What's New in GitLens 10</a
+						>
+					</div>
 					<p class="blurb ml-0 mr-0">
 						GitLens, while <b>powerful and feature rich</b>, is also highly <b>customizable</b> to meet your
 						needs. Do you find code lens intrusive or the current line blame annotation distracting &mdash;