Trigger for the last day of the month

Configuration
6

I got it, just had to single quote the 01 in the Binary sensor.

#last Day of the month Sensor
  - platform: template
    sensors:
      last_day_of_the_month:
        friendly_name: 'Last Day of the Month'
        entity_id: sensor.date
        icon_template: "mdi:calendar"
        value_template: "{{ (as_timestamp(now()) + 86400)|timestamp_custom('%d', true) == '01' }}"