Add docs for ClimaCell integration (#13698)

Co-authored-by: Franck Nijhof <git@frenck.dev>

.textlintrc.json

@@ -78,6 +78,7 @@
         "CardDAV",
         "Cisco IOS",
         "CLI",
+        "ClimaCell",
         "Daikin",
         "Danfoss",
         "Dark Sky",

source/_integrations/climacell.markdown

@@ -0,0 +1,31 @@
+---
+title: ClimaCell
+description: Instructions on how to integrate the ClimaCell Weather and Air Quality API into Home Assistant.
+ha_category:
+  - Weather
+ha_release: 2021.3
+ha_iot_class: Cloud Polling
+ha_config_flow: true
+ha_quality_scale: silver
+ha_codeowners:
+  - '@raman325'
+ha_domain: climacell
+---
+
+The ClimaCell integration allows you to obtain weather information from the [ClimaCell API](https://www.climacell.co/weather-api/).
+
+## Obtain an API key
+
+You can obtain a free API key by signing up with [ClimaCell](https://developer.climacell.co/sign-up?_ga=2.137889264.1908484805.1591592950-510691096.1591288729).
+
+The integration will automatically set the refresh interval based on the number of ClimaCell integrations that are using the same API key for a given Home Assistant instance. The integration currently assumes you are using a free account so the max requests per day is 1000. If you want to use a paid account to increase the number of max requests and increase the update frequency, please open a Home Assistant issue for the integration.
+
+## Supported Forecast Types
+
+| Forecast Type | Description                                                                                                      |
+|---------------|------------------------------------------------------------------------------------------------------------------|
+| `nowcast`     | Up to the 1 minute predictions. Supports 300 minutes or a max of 30 forecasts depending on the chosen `timestep` |
+| `hourly`      | Hourly forecasts for the next 24 hours                                                                           |
+| `daily`       | Daily  forecasts for the next 14 days                                                                            |
+
+{% include integrations/config_flow.md %}