docs: add sha256 checksums for 13.0.2

Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
(cherry picked from commit 2722144beddac0aa7065b478502c7c3a1f2a5451)
diff --git a/docs/relnotes/13.0.2.html b/docs/relnotes/13.0.2.html
index 5125b61..2f50199 100644
--- a/docs/relnotes/13.0.2.html
+++ b/docs/relnotes/13.0.2.html
@@ -31,7 +31,8 @@
 
 <h2>SHA256 checksums</h2>
 <pre>
-TBD
+6014233a5db6032ab8de4881384871bbe029de684502707794ce7b3e6beec308  mesa-13.0.2.tar.gz
+a6ed622645f4ed61da418bf65adde5bcc4bb79023c36ba7d6b45b389da4416d5  mesa-13.0.2.tar.xz
 </pre>