Fix grpc issue in gitlab-ce

• While I'm here, use = instead of ?= because gitlab-ce does not have slave port
• Bump PORTREVISION for dependency change

gitlab-ce has some runtime issue with grpc versions, especially upb stuff.
Move all gitlab-ce dependencies to specific grpc/rubygem-grpc versions in order
to keep gitlab-ce port more robust.

The changes are as follows:

• Add devel/grpc134 (copied from devel/grpc)
• Add net/rubygem-grpc130 (copied from net/rubygem-grpc)
• Move gitlab-ce and its dependencies to grpc134 and rubygem-grpc130

Differential Revision: https://reviews.freebsd.org/D28491
Submitted by: sunpoet (myself)
Approved by: mfechner
Tested by: mfechner