build-unit-test-docker: function2: update to 4.2.4

The 4.2.4 release is now used in upstream poky.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Id6802d7a9e191478ad0f2bb07121dd718eb6ff0e
diff --git a/scripts/build-unit-test-docker b/scripts/build-unit-test-docker
index 6ace781..35ed069 100755
--- a/scripts/build-unit-test-docker
+++ b/scripts/build-unit-test-docker
@@ -125,7 +125,7 @@
         ],
     ),
     "Naios/function2": PackageDef(
-        rev="4.2.1",
+        rev="4.2.4",
         build_type="custom",
         build_steps=[
             f"mkdir {prefix}/include/function2",