transfer: add deprecation notice (#7372)

Fixes #7371
Signed-off-by: Arvindraj <arvindultimate7352@gmail.com>
Co-authored-by: Stephen Ward <stephen@whilenotzero.com>

plugins/transfer/README.md

 # `transfer` plugin
 
+**NOTICE: The `transfer` plugin is deprecated and will be removed soon, since the [transfer.sh](https://transfer.sh) service will be shutdown on 30th November 30th, 2018. Please move your files to an alternative file sharing service provider.**
+
+----
+
 [`transfer.sh`](https://transfer.sh) is an easy to use file sharing service from the command line
 
 ## Usage

plugins/transfer/transfer.plugin.zsh

@@ -12,6 +12,14 @@
 #   Modified to use tar command instead of zip
 #
 
+echo -ne '\e[1;33m'
+cat <<-EOF
+        [oh-my-zsh] WARNING: The 'transfer' plugin is deprecated and will be removed after
+        [oh-my-zsh] transfer.sh shuts down on November 30th. We suggest you stop using the
+        [oh-my-zsh] plugin and find an alternative file hosting service.
+EOF
+echo -ne '\e[0m'
+
 curl --version 2>&1 > /dev/null
 if [ $? -ne 0 ]; then
   echo "Could not find curl."