[PATCH] doc: add GRE option flow item to feature list

[Thomas Monjalon]

25/02/2022 19:27, Ferruh Yigit:
> 'gre_option' flow item was missing in the feature list, adding it.
> 
> Fixes: f61490bdf218 ("ethdev: support GRE optional fields")
> 
> Signed-off-by: Ferruh Yigit <ferruh.yigit at intel.com>

Acked-by: Thomas Monjalon <thomas at monjalon.net>