ssz: bump (#6155)

arnetheduck · tersec · commit 79898934dccc · 2024-03-29T01:17:35.000Z
should fix `dereferencing pointer to incomplete type` errors seen on
some gcc versions
diff --git a/vendor/nim-ssz-serialization b/vendor/nim-ssz-serialization
@@ -1 +1 @@
-Subproject commit 0fc5e49093fa8d3c07476738e3257d0d8e7999a3
+Subproject commit 248f2bdca2d65ff920920c72b764d0622d522596
