[google-cloud-cpp] update to latest release (v2.18.0)

[alevenberg]

Updates google-cloud-cpp to the latest release (v2.18.0)

Tested locally (on x64-linux) with:

for feature in securesourcemanager; do ./vcpkg remove google-cloud-cpp; ./vcpkg install "google-cloud-cpp[core,${feature}]" || break; done

and

./vcpkg remove google-cloud-cpp && ./vcpkg install 'google-cloud-cpp[*]'

• Changes comply with the maintainer guide
• SHA512s are updated for each updated download
• The "supports" clause reflects platforms that may be fixed by this new version
• Any fixed CI baseline entries are removed from that file.
• Any patches that are no longer applied are deleted from the port's directory.
• The version database is fixed by rerunning ./vcpkg x-add-version --all and committing the result.
• Only one version is added to each modified port's versions file.

[alevenberg]

@microsoft-github-policy-service agree company="Google"

[alevenberg]

The CI seems to be giving unrelated errors.

,##[error]We stopped hearing from agent vcpkg-eg-mac-08. Verify the agent machine is running and has a healthy network connection. Anything that terminates an agent process, starves it for CPU, or blocks its network access can cause this error. For more information, see: https://go.microsoft.com/fwlink/?linkid=846610

Can one of the maintainers take a look?

[alevenberg]

@jimwang118 Can you take a look when you get the chance?