vendor: cream pie the themes

Change-Id: I2d5e554396145e35d0b0f2524b431fafd86bf378
diff --git a/google/themes/NotificationsPrimary/Android.mk b/google/themes/NotificationsPrimary/Android.mk
index d5ce1fe..dcced9e 100644
--- a/google/themes/NotificationsPrimary/Android.mk
+++ b/google/themes/NotificationsPrimary/Android.mk
@@ -5,6 +5,7 @@
 LOCAL_RRO_THEME := NotificationsPrimary
 LOCAL_CERTIFICATE := platform
 LOCAL_MODULE_TAGS := optional
+LOCAL_SDK_VERSION := 28
 LOCAL_SRC_FILES := $(call all-subdir-java-files)
 LOCAL_RESOURCE_DIR := $(LOCAL_PATH)/res