Support for GDEW0213M21 display

[vidhill]

Hello,

I was attempting to use this library with the GDEW0213M21 display

I noted that that display is not included in the library,

I did however find an implementation of it in a number of places,

I cannot seem to work out who originally wrote the implementation,
(the author name in the source is your name, but that could have been a copy/paste)

e.g.

• https://github.com/ltsochev-dev/esp32-weather-station/tree/main/lib/GxEPD/src/GxGDEW0213M21
• https://github.com/search?q=%23define+GxGDEW0213M21_WIDTH+104&type=Code

I make no claim to have written the code in this PR,
the implementation does work for me however , so I thought it may be of use to somebody else..

See also: Xinyuan-LilyGO/LilyGo-T5-Epaper-Series#26