Update showcase

Author: knolleary

index.html

@@ -121,7 +121,7 @@ <h4>In the cloud</h4>
         <div class="content">
             <h3>Who's using Node-RED?</h3>
             <ul id="user-list">
-                <li><a href="https://www.prescientdevices.com/"><img src="users/pdi-logo.svg"/></a></li>
+                <li><a href="https://www.prescientdevices.com/"><img src="users/pdi-logo.png"/></a></li>
                 <li><a href="https://handy.ai/"><img src="users/handyai.svg"/></a></li>
                 <li><a href="https://simplehw.eu/"><img src="users/simplehw.png"/></a></li>
                 <li><a href="https://openiap.io/"><img src="users/openiap.png"/></a></li>