Update version info for v1.0-rc1

Signed-off-by: Nico Huber <nico.h@gmx.de>
diff --git a/versioninfo.inc b/versioninfo.inc
index 5013016..6ac75ca 100644
--- a/versioninfo.inc
+++ b/versioninfo.inc
@@ -1,2 +1,2 @@
-VERSION = 1.0.x
+VERSION = v1.0-rc1
 MAN_DATE = 2023-09-18