RAUC: mark a modified git checkout appropriately in image metadata

...so that it's visible even in `rauc status --detailed`.

Change-Id: Idb73d68f59cc53a89fb22b33836de837e7ff47f4
diff --git a/package/czechlight-rauc/czechlight-rauc.mk b/package/czechlight-rauc/czechlight-rauc.mk
index 08a1e0c..85d23a2 100644
--- a/package/czechlight-rauc/czechlight-rauc.mk
+++ b/package/czechlight-rauc/czechlight-rauc.mk
@@ -5,7 +5,7 @@
 	$(RM) -rf $(CZECHLIGHT_RAUC_TMP_TARGET_DIR)
 	mkdir -p $(CZECHLIGHT_RAUC_TMP_TARGET_DIR)
 	sed \
-		-e 's|CZECHLIGHT_RAUC_IMAGE_VERSION|$(call qstrip,$(shell git --git-dir=$(BR2_EXTERNAL_CZECHLIGHT_PATH)/.git describe))|' \
+		-e 's|CZECHLIGHT_RAUC_IMAGE_VERSION|$(call qstrip,$(shell git --git-dir=$(BR2_EXTERNAL_CZECHLIGHT_PATH)/.git describe --dirty))|' \
 		-e 's|CZECHLIGHT_RAUC_COMPATIBLE|$(call qstrip,$(CZECHLIGHT_RAUC_COMPATIBLE))|' \
 		$(BR2_EXTERNAL_CZECHLIGHT_PATH)/package/czechlight-rauc/rauc-manifest.raucm.in \
 		> $(CZECHLIGHT_RAUC_TMP_TARGET_DIR)/manifest.raucm