Add support for grpcs protocol

[theFra985]

No description provided.

[buchdag]

Hi. I'm not sure I understand the point of this PR. The added code is already there under the grpc proto.

[theFra985]

Hi, sorry for the late reply, it would support grpcs if it had an option to prefix the grpc_pass URL with grpcs instead of grpc.
My issue was the lack of grpcs:// protocol support as the rule added in the grpc PR doesn't include the grpcs protocol while matching the specified protocol and while deploying PMM under nginx-proxy it was required to have grpcs:// as the protocol instead of grpc:// for it to work properly.
An alternative would be to match both of them in the same condition but the grpc PR lacks an option to use grpcs:// as protocol in the grpc_pass call

[buchdag]

@theFra985 my bad, I misunderstood the change.