Let lint-protovalidate depend on the buf target

Author: timostamm

Makefile

@@ -58,8 +58,8 @@ lint-proto: | $(BIN)/buf
 	$(MAKE) lint-protovalidate
 
 .PHONY: lint-protovalidate
-lint-protovalidate:
-	$(GO) run ./tools/internal/protovalidate-check proto/protovalidate
+lint-protovalidate: | $(BIN)/buf  # Check invariants of validate.proto
+	PATH="$(abspath $(BIN)):$$PATH" $(GO) run ./tools/internal/protovalidate-check proto/protovalidate
 
 .PHONY: conformance
 conformance: ## Build conformance harness