glibmm-2.68: upgrade 2.88.1 -> 2.90.0

Same conflict as in the 2.66 series; 2.90.0 carries the fix. The API
version stays 2.68, so the pkg-config names are unchanged.

Depends on the glib-2.0 2.90.0 upgrade in oe-core.

AI-Generated: Uses Claude Code (Claude Opus 5)
Signed-off-by: Markus Volk <f_l_k@t-online.de>
Signed-off-by: Khem Raj <khem.raj@oss.qualcomm.com>

meta-oe/recipes-core/glib-2.0/glibmm-2.68_2.90.0.bb

@@ -12,7 +12,7 @@ inherit gnomebase
 
 SHRT_VER = "${@d.getVar('PV').split('.')[0]}.${@d.getVar('PV').split('.')[1]}"
 
-SRC_URI[archive.sha256sum] = "c139f962b1575c8827cd39d1ac21b7a367be3bda1409c0c7e21a29090f371506"
+SRC_URI[archive.sha256sum] = "e2efa45643f16b9fea2d6299f2f403d672eaeacddf0ff7f8094e1af9b0f5980b"
 
 S = "${UNPACKDIR}/${GNOMEBN}-${PV}"