Set useragent for feed request

feed.go

@@ -3,6 +3,7 @@ package main
 import (
 	"encoding/json"
 	"errors"
+	"fmt"
 	"io/ioutil"
 	"net/http"
 )
@@ -13,7 +14,12 @@ func allFeedItems(url string) ([]string, error) {
 			Url string `json:"url"`
 		} `json:"items"`
 	}{}
-	resp, err := http.DefaultClient.Get(url)
+	req, err := http.NewRequest(http.MethodGet, url, nil)
+	if err != nil {
+		return nil, errors.New("failed to create req to get json feed")
+	}
+	req.Header.Add("User-Agent", fmt.Sprintf("%s %s", libName, version))
+	resp, err := http.DefaultClient.Do(req)
 	if err != nil {
 		return nil, errors.New("failed to get json feed")
 	}