Update mkdocs.yml to the latest release (1.15.3)

bsideup · web-flow · commit 3a6e77e920c0 · 2021-04-20T16:51:15.000+02:00
diff --git a/mkdocs.yml b/mkdocs.yml
@@ -96,4 +96,4 @@ nav:
           - contributing_docs.md
           - bounty.md
 extra:
-    latest_version: 1.15.2
+    latest_version: 1.15.3
