python3Packages.pyowm: drop outdated patching
python3Packages.pyowm: drop outdated patching

Version 2.10 relaxed the requirement for geojson from
`geojson>=2.3.0,<2.4` to `geojson>=2.3.0,<3`. Remove the postPatch hook
that adjusted this requirement when it broke in nixpkgs.

NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs