Increase max_temp for Shelly devices

Based on the following resources:

  - https://community.home-assistant.io/t/shelly-2-5-getting-hot-to-touch-63-c-external-case-should-i-be-worried/175376/36
  - arendst/Tasmota#10976
  - arendst/Tasmota#7991
  - https://community.home-assistant.io/t/shelly-thermal-protection-threshold/167494/4

esphome/devices/shelly/common.yaml

@@ -3,7 +3,7 @@ substitutions:
   device_board: 'esp01_1m'
   device_platform: 'ESP8266'
   max_power: '2000.0'
-  max_temp: '80.0'
+  max_temp: '90.0'
 
   # NOTE: See esphome/issues#1532.
   wifi_power_save_mode: 'high'