do not error out when go.mod is missing just raise warning, change linter options

Author: ryancurrah

pkg/golinters/gomodguard.go

@@ -59,7 +59,9 @@ func NewGomodguard() *goanalysis.Linter {
 
 			processor, err := gomodguard.NewProcessor(processorCfg, log.New(os.Stderr, "", 0))
 			if err != nil {
-				return nil, err
+				lintCtx.Log.Warnf("running gomodguard failed: %s: if you are not using go modules "+
+					"it is suggested to disable this linter", err)
+				return nil, nil
 			}
 
 			gomodguardErrors := processor.ProcessFiles(files)

pkg/lint/lintersdb/manager.go

@@ -249,6 +249,7 @@ func (m Manager) GetAllSupportedLinterConfigs() []*linter.Config {
 			WithURL("https://github.com/tommy-muehle/go-mnd"),
 		linter.NewConfig(golinters.NewGomodguard()).
 			WithPresets(linter.PresetStyle).
+			WithLoadForGoAnalysis().
 			WithURL("https://github.com/rcurrah/gomodguard"),
 	}