force --no-cache in reproduce mode

Makefile

@@ -9,6 +9,7 @@ export
 ## Use env vars from latest release when reproducing
 ifdef REPRODUCE
 include dist/release.env
+NO_CACHE := --no-cache
 export
 endif
 
@@ -30,6 +31,7 @@ out/airgap.iso: Containerfile $(shell git ls-files rootfs)
 		--build-arg GIT_AUTHOR="$(GIT_AUTHOR)" \
 		--build-arg GIT_KEY="$(GIT_KEY)" \
 		--build-arg GIT_TIMESTAMP="$(GIT_TIMESTAMP)" \
+		$(NO_CACHE) \
 		-f Containerfile \
 		.