fix(deps): require google-api-core>=1.31.5, >=2.3.2

[parthea]

fix(deps): require google-auth 1.25.0

[busunkim96]

The google-auth pin also needs to be increased:

ERROR: Cannot install google-cloud-core and google-cloud-core==2.2.2 because these package versions have conflicting dependencies.

The conflict is caused by:
    google-cloud-core 2.2.2 depends on google-auth<3.0dev and >=1.24.0
    google-api-core 1.[31](https://github.com/googleapis/python-cloud-core/runs/5407205326?check_suite_focus=true#step:5:31).5 depends on google-auth<2.0dev and >=1.25.0
    The user requested (constraint) google-auth==1.24.0

To fix this you could try to:
1. loosen the range of package versions you've specified
2. remove package versions to allow pip attempt to solve the dependency conflict

[Ark-kun]

require google-api-core>=1.31.5, >=2.3.2

Hmm. The 2.3.1 seems to be permitted by the requirements.