Merge draft release notes for third RC of 1.6.0.

Author: necouchman

_releases/1.6.0.md

@@ -2,14 +2,14 @@
 
 released: false
 title: 1.6.0
-date: 2025-06-16 15:49:35 -0700
+date: 2025-06-19 14:50:41 -0700
 summary: >
     Improved rendering performance, improved Docker support, configurable case
     sensitivity, batch connection import, support Duo v4.
 
 artifact-url: "https://dist.apache.org/repos/dist/dev/{}"
 checksum-url: "https://dist.apache.org/repos/dist/dev/{}"
-download-path: "guacamole/1.6.0-RC2/"
+download-path: "guacamole/1.6.0-RC3/"
 checksum-suffixes:
     "PGP"     : ".asc"
     "SHA-256" : ".sha256"