docs: add sha256 checksums for 12.0.1

Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
(cherry picked from commit edfc17a19a17e8dae41a703a9cb4b9eb3c255c34)
diff --git a/docs/relnotes/12.0.1.html b/docs/relnotes/12.0.1.html
index be2eaca..1571f48 100644
--- a/docs/relnotes/12.0.1.html
+++ b/docs/relnotes/12.0.1.html
@@ -33,7 +33,8 @@
 
 <h2>SHA256 checksums</h2>
 <pre>
-TBD.
+28dff9c045f4305c96a875a487b9f06c7e88d910511cd6016dbddcd1f53ade0d  mesa-12.0.1.tar.gz
+bab24fb79f78c876073527f515ed871fc9c81d816f66c8a0b051d8d653896389  mesa-12.0.1.tar.xz
 </pre>