docs: add sha256 checksums for 19.1.7

Signed-off-by: Juan A. Suarez Romero <jasuarez@igalia.com>
(cherry picked from commit b9d7244035ce2da5bd93c984e30944b3730b219e)
diff --git a/docs/relnotes/19.1.7.html b/docs/relnotes/19.1.7.html
index d83d87b..e91ae6f 100644
--- a/docs/relnotes/19.1.7.html
+++ b/docs/relnotes/19.1.7.html
@@ -30,7 +30,7 @@
 
 <h2>SHA256 checksums</h2>
 <pre>
-TBD
+e287920fdb38712a9fed448dc90b3ca95048c7face5db52e58361f8b6e0f3cd5  mesa-19.1.7.tar.xz
 </pre>