Add syslog generation when LibreNMS got updated

Hello team,

We have a LibreNMS with script enabled for auto updates. We would like to receive Slack notifications every time it got updated or failed to update. We would like to generate syslog messages from script to local syslog and based on these syslogs we can generate alerts and send them to Slack.

Here is a code that we would like to propose:

# Check if we need to revert (Must be in post pull so we can update it)
if [[ "$old_version" != "$new_version" ]]; then
    check_dependencies # check php and python version and switch branches

    # Add timestamp and hostname to the status message
    timestamp=$(date +"%Y-%m-%dT%H:%M:%S.%N%z")
    status_message="$timestamp $hostname %LIBRENMS_UPGRADE_SUCCESS: LibreNMS Updated from $old_version to $new_version on $hostname"

    # Output status message to syslog and standard output
    logger -t "LibreNMS" "$status_message"
    status_run "$status_message" ''

    set_notifiable_result update 1  # only clear the error if update was a success

Please let us know if it works and we can submit PR.

Best regards,