Use a list of releases in the template printer

This makes the template output more flexible; e.g. it is possible to
display only the first item of a release list (i.e. the latest release
of a project) if there are more than one with "{{with index . 0}}"...

gh/printer/templateprinter.go

@@ -74,18 +74,16 @@ func (p *TemplatePrinter) PrintReleases(rr []gh.ReleaseList) error {
 	}
 
 	for _, rl := range rr {
-		for _, r := range rl {
-			data, err := json.Marshal(r)
-			if err != nil {
-				return err
-			}
-			out := map[string]interface{}{}
-			if err := json.Unmarshal(data, &out); err != nil {
-				return err
-			}
-			if err = p.safeExecute(os.Stdout, out); err != nil {
-				return fmt.Errorf("error executing template %q: %v", p.rawTemplate, err)
-			}
+		data, err := json.Marshal(rl)
+		if err != nil {
+			return err
+		}
+		out := []map[string]interface{}{}
+		if err := json.Unmarshal(data, &out); err != nil {
+			return err
+		}
+		if err = p.safeExecute(os.Stdout, out); err != nil {
+			return fmt.Errorf("error executing template %q: %v", p.rawTemplate, err)
 		}
 	}
 	return nil

ghreleasechecker.yaml

@@ -28,5 +28,5 @@ printer:
     show_body: false
   template_printer:
     color_mode: 'auto'
-    template: '{{color ",,bold"}}{{.repo}}{{color "reset"}} {{color "red"}}{{.version}}{{color "reset"}} {{.tag}} {{.publish_date | tolocal}}{{"\n"}}'
+    template: '{{range .}}{{color ",,bold"}}{{.repo}}{{color "reset"}} {{color "red"}}{{.version}}{{color "reset"}} {{.tag}} {{.publish_date | tolocal}}{{"\n"}}{{end}}'
 ...