Release notes for cobrapy 0.22.1

Fixes

Fix an old bug with double gene deletion that was not knocking-out combinations (#1103).
Lots of syntax, annotation, and docstring fixes (#1081, #1083, #1084, #1085, #1086, #1088, #1090, #1091, #1092, #1093, #1094, #1095, #1096).

Deprecated features

find_gene_knockout_reactions is deprecated.