add deprecated boards doc page about boards that have been deprecated

Author: umbynos

docs/deprecated.md

@@ -0,0 +1,18 @@
+# Deprecated boards
+
+## MKR 1000
+
+The [Arduino MKR 1000] has been deprecated during the migration to the [plugin] system because the board has reached
+it's EOL state. If you wish to update the firmware it's still possible by using version [2.3.0] of the Arduino Firmware
+Uploader.
+
+## MKR Vidor 4000
+
+The [Arduino MKR Vidor 4000] has been deprecated during the migration to the [plugin] system because the board has
+reached it's EOL state. If you wish to update the firmware it's still possible by using version [2.3.0] of the Arduino
+Firmware Uploader.
+
+[Arduino MKR 1000]: https://docs.arduino.cc/hardware/mkr-1000-wifi
+[Arduino MKR Vidor 4000]: https://docs.arduino.cc/hardware/mkr-vidor-4000
+[2.3.0]: https://github.com/arduino/arduino-fwuploader/releases/tag/2.3.0
+[plugin]: plugins.md

mkdocs.yml

@@ -60,3 +60,4 @@ nav:
       - firmware list: commands/arduino-fwuploader_firmware_list.md
       - version: commands/arduino-fwuploader_version.md
   - Plugins: plugins.md
+  - Deprecated boards: deprecated.md