Fix compilation with GHC 8

Author: p1gp1g

src/Simplex/Messaging/Notifications/Server/Push/WebPush.hs

@@ -16,7 +16,7 @@ import Simplex.Messaging.Notifications.Server.Push
 import Control.Monad.Except
 import Control.Logger.Simple (logDebug)
 import Simplex.Messaging.Util (tshow)
-import qualified Data.ByteString.Char8 as B
+import qualified Data.ByteString as B
 import Control.Monad.IO.Class (liftIO)
 import Control.Exception ( fromException, SomeException, try )
 import qualified Network.HTTP.Types as N