build: add lint target

Jaime Fournier <jaimef@linbsd.org>

3566ed557b84aecfd3b0109cf732d8a0e7631802

diff --git a/Makefile b/Makefile
index 707e4f9..79f7dda 100644
--- a/Makefile
+++ b/Makefile
@@ -13,7 +13,7 @@ GENERATOR := support/generate/upstream-contracts.ss
 INVENTORY := contracts/generated/upstream-inventory.sexp
 UNIT_TESTS := $(wildcard test/unit/*.ss)
 
-.PHONY: all check-upstream contracts contracts-check unit test check-docs verify clean help
+.PHONY: all check-upstream contracts contracts-check unit test check-docs verify clean help lint
 .DEFAULT_GOAL := help
 
 all: verify
@@ -46,6 +46,8 @@ unit:
 
 test: unit
 
+lint: check-docs
+
 check-docs:
 	@test -s Project.md
 	@test -s README.md