Use golangci-lint (#1044)

Use golangci-lint. Repair warnings and errors resulting from linting.

Makefile

@@ -1,21 +1,29 @@
 BIN="./bin"
 SRC=$(shell find . -name "*.go")
 
+ifeq (, $(shell which golangci-lint))
+$(warning "could not find golangci-lint in $(PATH), run: curl -sfL https://install.goreleaser.com/github.com/golangci/golangci-lint.sh | sh")
+endif
+
 ifeq (, $(shell which richgo))
 $(warning "could not find richgo in $(PATH), run: go get github.com/kyoh86/richgo")
 endif
 
-.PHONY: fmt vet test cobra_generator install_deps clean
+.PHONY: fmt lint test cobra_generator install_deps clean
 
 default: all
 
-all: fmt vet test cobra_generator	
+all: fmt test cobra_generator
 
 fmt:
 	$(info ******************** checking formatting ********************)
 	@test -z $(shell gofmt -l $(SRC)) || (gofmt -d $(SRC); exit 1)
 
-test: install_deps vet
+lint:
+	$(info ******************** running lint tools ********************)
+	golangci-lint run -v
+
+test: install_deps lint
 	$(info ******************** running tests ********************)
 	richgo test -v ./...
 
@@ -28,9 +36,5 @@ install_deps:
 	$(info ******************** downloading dependencies ********************)
 	go get -v ./...
 
-vet:
-	$(info ******************** vetting ********************)
-	go vet ./...
-
 clean:
 	rm -rf $(BIN)