Support more recent Bazel versions

[martijneken]

When I remove .bazelversion (5.2.0) I get some build errors. One fix is below, I'll send a PR.

 # Upgrade googletest to v1.13.0 to support bazel 6+
 http_archive(
     name = "com_google_googletest",
     sha256 = "ad7fdba11ea011c1d925b3289cf4af2c66a352e18d4c7264392fead75e919363",
     strip_prefix = "googletest-1.13.0",
     url = "https://github.com/google/googletest/archive/v1.13.0.tar.gz",
 )

[PiotrSikora]

Could you paste the error that you're getting?

[martijneken]

Obsolete, Bazel is now 6.5.0 and Bazel 7 is tracked in #403