add "Plugin Gallery" to top menu

Author: sumpfralle

_includes/header.html

@@ -68,6 +68,7 @@ <h1 class="logo-wrap">
 					<a href="https://github.com/munin-monitoring/munin"><i class="mdi mdi-github-circle"></i> Munin on GitHub</a>
 					<a href="/documentation/" {% if page.url == '/documentation/' %}class="active"{% endif %}><i class="mdi mdi-file-document"></i> Documentation</a>
 					<a href="https://guide.munin-monitoring.org/"><i class="mdi mdi-book-open-variant"></i> Munin Guide</a>
+					<a href="https://gallery.munin-monitoring.org/"><i class="mdi mdi-beaker"></i> Plugin Gallery</a>
 					<a href="/news/" {% if page.url == '/news/' %}class="active"{% endif %}><i class="mdi mdi-newspaper"></i> News</a>
 				</div>
 			</div>