add setChatPhoto method

bot.go

@@ -922,3 +922,15 @@ func (bot *BotAPI) SetChatDescription(config SetChatDescriptionConfig) (APIRespo
 
 	return bot.MakeRequest(config.method(), v)
 }
+
+// SetChatPhoto change photo of chat.
+func (bot *BotAPI) SetChatPhoto(config SetChatPhotoConfig) (APIResponse, error) {
+	params, err := config.params()
+	if err != nil {
+		return APIResponse{}, err
+	}
+
+	file := config.getFile()
+
+	return bot.UploadFile(config.method(), params, config.name(), file)
+}

configs.go

@@ -1111,3 +1111,18 @@ func (config SetChatDescriptionConfig) values() (url.Values, error) {
 
 	return v, nil
 }
+
+// SetChatPhotoConfig contains information for change chat photo
+type SetChatPhotoConfig struct {
+	BaseFile
+}
+
+// name returns the field name for the Photo.
+func (config SetChatPhotoConfig) name() string {
+	return "photo"
+}
+
+// method returns Telegram API method name for sending Photo.
+func (config SetChatPhotoConfig) method() string {
+	return "setChatPhoto"
+}

helpers.go

@@ -653,3 +653,34 @@ func NewInvoice(chatID int64, title, description, payload, providerToken, startP
 		Currency:       currency,
 		Prices:         prices}
 }
+
+// NewSetChatPhotoUpload creates a new chat photo uploader.
+//
+// chatID is where to send it, file is a string path to the file,
+// FileReader, or FileBytes.
+//
+// Note that you must send animated GIFs as a document.
+func NewSetChatPhotoUpload(chatID int64, file interface{}) SetChatPhotoConfig {
+	return SetChatPhotoConfig{
+		BaseFile: BaseFile{
+			BaseChat:    BaseChat{ChatID: chatID},
+			File:        file,
+			UseExisting: false,
+		},
+	}
+}
+
+// NewSetChatPhotoShare shares an existing photo.
+// You may use this to reshare an existing photo without reuploading it.
+//
+// chatID is where to send it, fileID is the ID of the file
+// already uploaded.
+func NewSetChatPhotoShare(chatID int64, fileID string) SetChatPhotoConfig {
+	return SetChatPhotoConfig{
+		BaseFile: BaseFile{
+			BaseChat:    BaseChat{ChatID: chatID},
+			FileID:      fileID,
+			UseExisting: true,
+		},
+	}
+}