20191215 code improvements (#790)

* Upgrade godo to latest
* Fix a bunch of issues found by
* Running staticcheck on a codebase for the first time is a sobering experience
* go mod tidy
* More static improvements

Signed-off-by: Chris Cummer <chriscummer@me.com>

modules/buildkite/settings.go

@@ -7,11 +7,18 @@ import (
 	"os"
 )
 
+const (
+	defaultTitle     = "Buildkite"
+	defaultFocusable = true
+)
+
+// PipelineSettings defines the configuration properties for a pipeline
 type PipelineSettings struct {
 	slug     string
 	branches []string
 }
 
+// Settings defines the configuration properties for this module
 type Settings struct {
 	common    *cfg.Common
 	apiKey    string             `help:"Your Buildkite API Token"`
@@ -19,9 +26,7 @@ type Settings struct {
 	pipelines []PipelineSettings `help:"An array of pipelines to get data from"`
 }
 
-const defaultTitle = "Buildkite"
-const defaultFocusable = true
-
+// NewSettingsFromYAML creates a new settings instance from a YAML config block
 func NewSettingsFromYAML(name string, ymlConfig *config.Config, globalConfig *config.Config) *Settings {
 	settings := Settings{
 		common:    cfg.NewCommonSettingsFromModule(name, defaultTitle, defaultFocusable, ymlConfig, globalConfig),
@@ -33,10 +38,12 @@ func NewSettingsFromYAML(name string, ymlConfig *config.Config, globalConfig *co
 	return &settings
 }
 
+/* -------------------- Unexported Functions -------------------- */
+
 func buildPipelineSettings(ymlConfig *config.Config) []PipelineSettings {
 	pipelines := []PipelineSettings{}
 
-	for slug, _ := range ymlConfig.UMap("pipelines") {
+	for slug := range ymlConfig.UMap("pipelines") {
 		branches := utils.ToStrs(ymlConfig.UList("pipelines." + slug + ".branches"))
 		if len(branches) == 0 {
 			branches = []string{"master"}