docs: update calendar, add news item and link release notes for 17.1.3

Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
diff --git a/docs/relnotes.html b/docs/relnotes.html
index 7ff34eb..6517594 100644
--- a/docs/relnotes.html
+++ b/docs/relnotes.html
@@ -21,6 +21,7 @@
 </p>
 
 <ul>
+<li><a href="relnotes/17.1.3.html">17.1.3 release notes</a>
 <li><a href="relnotes/17.1.2.html">17.1.2 release notes</a>
 <li><a href="relnotes/17.0.7.html">17.0.7 release notes</a>
 <li><a href="relnotes/17.1.1.html">17.1.1 release notes</a>