New Parquet-format release for Variant type

[aihuaxu]

Describe the enhancement requested

Variant logical type has been added to Parquet.thrift. In order to be used by parquet-format-structures and parquet-hadoop, seems we need to release a new Parquet-format version so new Parquet.thrift can be pulled.

[wgtmac]

Yes, usually the PoC implementation cannot pass CI due to dependency on an unreleased format. I'd like to include #240 to the next release as well.