support cachetools >= 6

[ericbuehl]

cachetools 6.0 has been available since May 23 2025 but it is unsupported in google-auth

google-auth-library-python/setup.py

Line 23 in ca94ead

"cachetools>=2.0.0,<6.0",

[harkamaljot]

We already have a open pull request here: #1773 I will try it get it merged this week.

[harkamaljot]

I merged the pull request, so the update should go in the next release, hence closing this issue out.

[mtvx]

@harkamaljot Any change for a new release?