rename 'Gettting new messages' to 'Updating'

see https://github.com/deltachat/deltachat-android/pull/1984
for reasoning.

DcCore/DcCore/Helper/DcUtils.swift

@@ -161,7 +161,7 @@ public struct DcUtils {
         if connectivity >= DC_CONNECTIVITY_CONNECTED {
             return connectedString
         } else if connectivity >= DC_CONNECTIVITY_WORKING {
-            return String.localized("connectivity_getting_new_msgs")
+            return String.localized("connectivity_updating")
         } else if connectivity >= DC_CONNECTIVITY_CONNECTING {
           return String.localized("connectivity_connecting")
         } else {