Update version to 19.1.0-rc3

Signed-off-by: Juan A. Suarez Romero <jasuarez@igalia.com>
diff --git a/VERSION b/VERSION
index f956271..327ea15 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-19.1.0-rc2
+19.1.0-rc3