docs: add sha256 checksums for 10.6.9

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
diff --git a/docs/relnotes/10.6.9.html b/docs/relnotes/10.6.9.html
index df4ff08..9d155fa 100644
--- a/docs/relnotes/10.6.9.html
+++ b/docs/relnotes/10.6.9.html
@@ -31,7 +31,8 @@
 
 <h2>SHA256 checksums</h2>
 <pre>
-TBD
+3406876aac67546d0c3e2cb97da330b62644c313e7992b95618662e13c54296a  mesa-10.6.9.tar.gz
+b04c4de6280b863babc2929573da17218d92e9e4ba6272d548d135415723e8c3  mesa-10.6.9.tar.xz
 </pre>