Add missing googleChat.messageformat

Signed-off-by: KeisukeYamashita <19yamashita15@gmail.com>

README.md

@@ -243,6 +243,7 @@ googleChat:
   webhookurl: "" # Google Chat WebhookURL (ex: https://chat.googleapis.com/v1/spaces/XXXXXX/YYYYYY), if not empty, Google Chat output is enabled
   # outputformat: "" # all (default), text
   # minimumpriority: "" # minimum priority of event for using this output, order is emergency|alert|critical|error|warning|notice|informational|debug or "" (default)
+  messageformat: "Alert : rule *{{ .Rule }}* triggered by user *{{ index .OutputFields \"user.name\" }}*" # a Go template to format Google Chat Text above Attachment, displayed in addition to the output from `GOOGLECHAT_OUTPUTFORMAT`, see [Slack Message Formatting](#slack-message-formatting) in the README for details. If empty, no Text is displayed before Attachment.
 ```
 
 Usage :

outputs/slack.go

@@ -41,7 +41,6 @@ func newSlackPayload(falcopayload types.FalcoPayload, config *types.Configuratio
 	var field slackAttachmentField
 
 	if config.Slack.OutputFormat == All || config.Slack.OutputFormat == Fields || config.Slack.OutputFormat == "" {
-		log.Print("not text!")
 		for i, j := range falcopayload.OutputFields {
 			switch v := j.(type) {
 			case string:
@@ -120,8 +119,6 @@ func newSlackPayload(falcopayload types.FalcoPayload, config *types.Configuratio
 	// 	iconURL = config.Slack.Icon
 	// }
 
-	log.Println(messageText)
-
 	s := slackPayload{
 		Text:        messageText,
 		Username:    config.Slack.Username,