doc: update calendar, add news and link release notes for 18.1.1
diff --git a/docs/relnotes.html b/docs/relnotes.html
index 568615d..a4a3eb2 100644
--- a/docs/relnotes.html
+++ b/docs/relnotes.html
@@ -21,6 +21,7 @@
 </p>
 
 <ul>
+<li><a href="relnotes/18.1.1.html">18.1.1 release notes</a>
 <li><a href="relnotes/18.1.0.html">18.1.0 release notes</a>
 <li><a href="relnotes/18.0.4.html">18.0.4 release notes</a>
 <li><a href="relnotes/18.0.3.html">18.0.3 release notes</a>