Keep a few downstream patches:
- Oauth2 PKCE initial support (76df15690c5b3e7fd2f97177cd8e743546821f07)
- Find QtKeychain by its cmake target
(b9e859f0ed1d9d783c0a7b4f28e3d73ac21572f6)
- Allow compiling o2 with Qt6 (6fbe9a4fb3a29bbbd32987153303181d3d4362cd)
- Hide more debug noise (1f91895b1e8d4ca8dd2bb24b0ea35f5bcb425a96)
- If an o2 auth refresh reply contains an error message, then
the refresh was NOT successful
(9af5a531b1a9c4b452b98c0a10387aefa850edee)
- Ensure correct thread locale QgsNetworkAccessManager is used during
o2 requests (9cde65457b3717a74e32277c843a2945eb4f1221)
