Added OpenERZ API integration documentation (#11619)

* Added OpenERZ API integration documentation

* Review fixes

* ✏️ Tweak

* Correct postcode type

* ⬆️ Bump ha_version to 0.109

Co-authored-by: Klaas Schoute <klaas_schoute@hotmail.com>
Co-authored-by: Franck Nijhof <git@frenck.dev>

source/_integrations/openerz.markdown

@@ -0,0 +1,40 @@
+---
+title: "OpenERZ Sensor"
+description: "Instructions on how to integrate a OpenERZ API for Zurich city waste disposal with Home Assistant"
+ha_category:
+  - Sensor
+ha_release: 0.109
+ha_iot_class: Cloud Polling
+---
+
+This `openerz` sensor platform uses [OpenERZ](http://openerz.metaodi.ch/) API to access data from Entsorgung und Recycling Zürich (ERZ). It reports the next pickup date for the specified zip and waste type.
+
+## Configuration
+
+To enable this sensor in your installation, add the following to your `configuration.yaml` file:
+
+```yaml
+# Example configuration.yaml entry
+sensor:
+  - platform: openerz
+    zip: 8001
+    waste_type: cardboard
+```
+
+Available (and tested) waste types are: `paper`, `cardboard`, `waste`, `cargotram`, `etram`, `organic` and `textile`.
+
+{% configuration %}
+name:
+  description: The name to be used when displaying this sensor.
+  required: false
+  type: string
+zip:
+  description: Postcode of the pickup location.
+  required: true
+  type: string
+waste_type:
+  description: Type of waste to be collected.
+  required: true
+  type: string
+  default: waste
+{% endconfiguration %}