devel/google-cloud-cpp: Unbreak with OpenSSL 3.0.0 and later

• Update version 1.21.0=>2.10.0

If the maintainer is in need of a version from the 1.X.X branch please
create a new posrt and assign me the ticket. The latest release of one
of the 1.X branch is also supposed to support OpenSSL 3.0.0 and later.

Changelog:
https://github.com/googleapis/google-cloud-cpp/releases/tag/v2.10.0
Approved by: portmgr (blanket)