Add composer.json support for psr/cache v3

[pbowyer]

This fixes the issue I reported at googleapis/google-cloud-php#5205.

When using PHP 8.1 it's becoming common to have packages that require psr/cache:^3 (in my case: symfony/cache-contracts:v3.0.0).

google/auth:v1.19.0 still requires psr/cache ^1.0|^2.0. This is preventing me from installing google/cloud-vision.

The only change with psr/cache:^3.0 is adding return types for PHP 8.0+, so you can support it as an option as it does not introduce any other changes.

[google-cla]

Thanks for your pull request! It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

For more information, open the CLA check for this pull request.

[pbowyer]

I've clicked the "rescan pull request" link after signing the CLA, submitted the form and... nothing 🤷‍♂️

[bshaffer]

This is being handled more robustly in #364

Please try using this branch by requiring it as an alias in composer.json and let me know if it works as you expect it to:

"google/auth": "dev-add-typed-cache-item as 1.20.0"

[bshaffer]

This is now released in v1.20.0

[pbowyer]

Thanks, tested and confirmed working 👍