Added pushbullet template.

Suggested and contributed by [@arpanghosh8453](https://github.com/arpanghosh8453)

README.md

@@ -84,6 +84,8 @@ Current templates:
 - Apprise (with it's [multitude](https://github.com/caronc/apprise#supported-notifications) of notifications)
   - both native [caronc/apprise](https://github.com/caronc/apprise) and the standalone [linuxserver/docker-apprise-api](https://github.com/linuxserver/docker-apprise-api)
   - Read the [QuickStart](extras/apprise_quickstart.md)
+- [ntfy.sh](https://ntfy.sh/) - HTTP-based pub-sub notifications.
+- [Pushbullet](https://www.pushbullet.com/) - connecting different devices with cross-platform features.
 
 Further additions are welcome - suggestions or PR!   
 <sub><sup>Initiated and first contributed by [yoyoma2](https://github.com/yoyoma2).</sup></sub>  

notify_pushbullet.sh

@@ -0,0 +1,27 @@
+### DISCLAIMER: This is a third party addition to dockcheck - best effort testing.
+#
+# Copy/rename this file to notify.sh to enable the notification snippet.
+# Required receiving services must already be set up.
+# Requires jq installed and in PATH.
+# Modify to fit your setup - set Url and Token.
+
+send_notification() {
+Updates=("$@")
+UpdToString=$( printf "%s\n" "${Updates[@]}" )
+FromHost=$(hostname)
+
+# platform specific notification code would go here
+printf "\nSending pushbullet notification\n"
+
+MessageTitle="$FromHost - updates available."
+# Setting the MessageBody variable here.
+MessageBody="Containers on $FromHost with updates available: $UpdToString"
+
+# Modify to fit your setup:
+PushUrl="https://api.pushbullet.com/v2/pushes"
+PushToken="Your Pushbullet token here"
+
+# Requires jq to process json data
+jq -n --arg title "$MessageTitle" --arg body "$MessageBody" '{body: $body, title: $title, type: "note"}' | curl -sS -o /dev/null --show-error --fail -X POST -H "Access-Token: $PushToken" -H "Content-type: application/json" $PushUrl -d @-
+
+}