Add go-mod Make target and use it (#7)

This commit adds a go-mod Make target to run "go mod download" and "go
mod tidy", then uses it so we have a nicer module.

Signed-off-by: John Schaeffer <jschaeffer@equinix.com>

Makefile

@@ -1,8 +1,13 @@
 PROTOC ?= $(shell which protoc)
 ROOT_DIR := $(shell dirname $(realpath $(firstword $(MAKEFILE_LIST))))
 
+.PHONY: go-mod
+go-mod:
+	@go mod download
+	@go mod tidy
+
 .PHONY: proto
-proto:
+proto: | go-mod
 	@$(PROTOC) --proto_path=$(ROOT_DIR)/proto \
                    --go_opt=paths=source_relative \
                    --go-grpc_opt=paths=source_relative \

go.sum

@@ -13,8 +13,6 @@ golang.org/x/text v0.11.0/go.mod h1:TvPlkZtksWOMsz7fbANvkp4WM8x/WCo/om8BMLbz+aE=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 google.golang.org/genproto/googleapis/rpc v0.0.0-20230711160842-782d3b101e98 h1:bVf09lpb+OJbByTj913DRJioFFAjf/ZGxEz7MajTp2U=
 google.golang.org/genproto/googleapis/rpc v0.0.0-20230711160842-782d3b101e98/go.mod h1:TUfxEVdsvPg18p6AslUXFoLdpED4oBnGwyqk3dV1XzM=
-google.golang.org/grpc v1.58.0 h1:32JY8YpPMSR45K+c3o6b8VL73V+rR8k+DeMIr4vRH8o=
-google.golang.org/grpc v1.58.0/go.mod h1:tgX3ZQDlNJGU96V6yHh1T/JeoBQ2TXdr43YbYSsCJk0=
 google.golang.org/grpc v1.58.3 h1:BjnpXut1btbtgN/6sp+brB2Kbm2LjNXnidYujAVbSoQ=
 google.golang.org/grpc v1.58.3/go.mod h1:tgX3ZQDlNJGU96V6yHh1T/JeoBQ2TXdr43YbYSsCJk0=
 google.golang.org/protobuf v1.26.0-rc.1/go.mod h1:jlhhOSvTdKEhbULTjvd4ARK9grFBp09yW+WbY/TyQbw=