Explicitly note that sponsorships are not refundable, thanks to Bradl…

…ey for the phrasing

Signed-off-by: Isaac Bennetch <bennetch@gmail.com>

pmaweb/templates/_sponsorship_conditions.html

@@ -2,6 +2,7 @@ <h3 id="rules">Sponsorship conditions and advantages</h3>
 
 <ul>
  <li>A sponsor has to commit to a yearly amount depending on the sponsorship level</li>
+ <li>Sponsorships are always on an annual basis and are <strong>not</strong> refundable once paid</li>
  <li>On one level, sponsors are listed in the chronological order of their adhesion to the sponsorship program</li>
  <li>We reserve the right to change sponsorship levels in the future</li>
  <li>The logo (if applicable) needs to be a static image, PNG is preferred</li>