Align version metadata to GoReleaser format

Makefile

@@ -1,9 +1,10 @@
-NAME      := k8stail
-VERSION   := v0.6.0
-REVISION  := $(shell git rev-parse --short HEAD)
+NAME    := k8stail
+VERSION := $(shell git tag | sort -V -r | head -n1)-next
+COMMIT  := $(shell git rev-parse HEAD)
+DATE    := $(shell date "+%Y-%m-%dT%H:%M:%S%z")
 
-SRCS      := $(shell find . -name '*.go' -type f)
-LDFLAGS   := -ldflags="-s -w -X \"main.Version=$(VERSION)\" -X \"main.Revision=$(REVISION)\""
+SRCS    := $(shell find . -name '*.go' -type f)
+LDFLAGS := -ldflags="-s -w -X \"main.version=$(VERSION)\" -X \"main.commit=$(COMMIT)\" -X \"main.date=$(DATE)\""
 
 .DEFAULT_GOAL := bin/$(NAME)
 

version.go

@@ -5,10 +5,11 @@ import (
 )
 
 var (
-	Version  string
-	Revision string
+	version string
+	commit  string
+	date    string
 )
 
 func printVersion() {
-	fmt.Printf("k8stail version %s, %s\n", Version, Revision)
+	fmt.Printf("k8stail version: %s, commit: %s, build at: %s\n", version, commit, date)
 }