fix golint issues, update codecov settings. (#1011)

* update codecov settings

* fix golint issues

tools/goctl/internal/errorx/errorx.go

@@ -12,6 +12,7 @@ var errorFormat = `goctl: generation error: %+v
 goctl version: %s
 %s`
 
+// GoctlError represents a goctl error.
 type GoctlError struct {
 	message []string
 	err     error

tools/goctl/internal/version/version.go

@@ -5,7 +5,8 @@ import (
 	"strings"
 )
 
-const BuildVersion = "1.1.11-beta-2"
+// BuildVersion is the version of goctl.
+const BuildVersion = "1.2.0"
 
 // GetGoctlVersion returns BuildVersion
 func GetGoctlVersion() string {