[orca] Update RELEASE-HOWTO to encourage signed tags

[Joanmarie Diggs <joanied src gnome org>]

commit f0f14020efacd095a62f94e4580513a5ae323e07
Author: Joanmarie Diggs <jdiggs igalia com>
Date:   Thu Jan 28 13:06:40 2021 +0100

    Update RELEASE-HOWTO to encourage signed tags

 RELEASE-HOWTO | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/RELEASE-HOWTO b/RELEASE-HOWTO
index 140c6f12b..3cec3292d 100644
--- a/RELEASE-HOWTO
+++ b/RELEASE-HOWTO
@@ -64,7 +64,7 @@ COMMIT RELEASE CHANGES AND TAG THE RELEASE:
 
 git commit -a
 git push
-git tag -a ORCA_2_29_92
+git tag -a -s ORCA_2_29_92
 git push origin ORCA_2_29_92