Use https for Navicat link, their side does redirect to it anyway

Signed-off-by: Michal Čihař <michal@cihar.com>

Author: nijel

pmaweb/templates/_sponsors.html

@@ -4,7 +4,7 @@
 <h3>Diamond sponsor</h3>
 
 <div class="sp diamond">
-<a href="http://www.navicat.com/"><img src="{% static 'images/navicat_250x250.jpg' %}" alt="Navicat" /></a>
+<a href="https://www.navicat.com/"><img src="{% static 'images/navicat_250x250.jpg' %}" alt="Navicat" /></a>
 </div>
 
 <h3>Gold sponsors</h3>

pmaweb/templates/sponsors.html

@@ -10,7 +10,7 @@ <h2>Sponsors</h2>
 </p>
 
 <h3>Diamond sponsor</h3>
-<a href="http://www.navicat.com/"><img src="{% static 'images/navicat_250x250.jpg' %}" alt="Navicat" /></a>
+<a href="https://www.navicat.com/"><img src="{% static 'images/navicat_250x250.jpg' %}" alt="Navicat" /></a>
 
 <h3>Platinum sponsors</h3>