Looks like the Makefile is doing unwanted substitution?
@echo "SWAGGER_GEN=`find pkg/generated/client pkg/generated/models/ pkg/generated/restapi/ -iname '*.go' | grep -v 'configure_rekor_server' | sort -d | tr '\n' ' ' | sed 's/ $$//'`" >> Makefile.swagger;
Originally posted by @pxp928 in #973 (comment)