Enable color output in govulncheck (go-gitea#34012)

Make `govulncheck` show color, which by default it doesn't for some
reason.

Author: silverwind

Makefile

@@ -737,7 +737,7 @@ generate-go: $(TAGS_PREREQ)
 
 .PHONY: security-check
 security-check:
-	go run $(GOVULNCHECK_PACKAGE) ./...
+	go run $(GOVULNCHECK_PACKAGE) -show color ./...
 
 $(EXECUTABLE): $(GO_SOURCES) $(TAGS_PREREQ)
 	CGO_CFLAGS="$(CGO_CFLAGS)" $(GO) build $(GOFLAGS) $(EXTRA_GOFLAGS) -tags '$(TAGS)' -ldflags '-s -w $(LDFLAGS)' -o $@