adding c6i to nvme families

[keviningvalson]

adding the c6i instances to the nvme families following convention seen in https://github.com/cloudfoundry/bosh-aws-cpi-release/pull/121/commits

[linux-foundation-easycla[bot]]

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• :white_check_mark: login: keviningvalson / name: Kevin Ingvalson (f4cde7d3b80b29ab3b6fa13c1051d6e62d6ec07e)

[rkoster]

Thanks! @keviningvalson