Corrected the diode generated device drawing routine in sky130.tcl
so that it does not create a port label on a substrate node, since
the substrate node is not represented in the diode subcircuit model.

VERSION

diff --git a/VERSION b/VERSION
index 624db48..0236e72 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-1.0.503
+1.0.504

sky130/magic/sky130.tcl

diff --git a/sky130/magic/sky130.tcl b/sky130/magic/sky130.tcl
index 69b6b22..64b689d 100644
--- a/sky130/magic/sky130.tcl
+++ b/sky130/magic/sky130.tcl
@@ -1549,7 +1549,7 @@
 	set gy [+ $corey [* 2.0 [+ $diff_spacing $diff_surround]] $contact_size]
 
 	# Draw the guard ring first, because diode may occupy well/substrate plane
-	if {$doports} {dict set parameters bulk B}
+	# (NOTE:  Diode models have no bulk terminal, so do not create a port)
 	sky130::guard_ring $gx $gy $parameters
     }