DeprecationWarning: Inheritance class AuthorizedSession from ClientSession is discouraged

[parthea]

See the build log here which contains the warning below.

google/auth/transport/_aiohttp_requests.py:200
  /tmpfs/src/github/google-auth-library-python/google/auth/transport/_aiohttp_requests.py:200: DeprecationWarning: Inheritance class AuthorizedSession from ClientSession is discouraged
    class AuthorizedSession(aiohttp.ClientSession):

This issue tracks fixing the underlying issue so that the warning is not emitted.

[hwlodarczyk-rtbh]

It seems that it may require different approach than inheritance for AuthorizedSession to borrow ClientSession implementation as one of aiohttp maintainers mentioned https://github.com/aio-libs/aiohttp/issues/3185#issuecomment-412326191 .