Add flags to running golangci-lint (#617)

Add `--modules-download-mode=readonly` and `--timeout=3m0s` to running
`golangci-lint`.

Makefile

@@ -46,13 +46,13 @@ install: ## Install all binaries
 .PHONY: lint
 lint: $(BIN)/golangci-lint $(BIN)/buf ## Lint Go and protobuf
 	go vet ./...
-	golangci-lint run
+	golangci-lint run --modules-download-mode=readonly --timeout=3m0s
 	buf lint
 	buf format -d --exit-code
 
 .PHONY: lintfix
 lintfix: $(BIN)/golangci-lint $(BIN)/buf ## Automatically fix some lint errors
-	golangci-lint run --fix
+	golangci-lint run --fix --modules-download-mode=readonly --timeout=3m0s
 	buf format -w
 
 .PHONY: generate