PARQUET-1221: Extend release README
PARQUET-1221: Extend release README

Author: Korn, Uwe <Uwe.Korn@blue-yonder.com>

Closes #441 from xhochy/PARQUET-1221 and squashes the following commits:

daa4778 [Korn, Uwe] PARQUET-1221: Extend release README [skip ci]

majetideepak/parquet-cpp,wesm/parquet-cpp,wesm/parquet-cpp,apache/parquet-cpp,wesm/parquet-cpp,majetideepak/parquet-cpp,majetideepak/parquet-cpp,apache/parquet-cpp,apache/parquet-cpp,wesm/parquet-cpp,apache/parquet-cpp,apache/parquet-cpp,majetideepak/parquet-cpp,wesm/parquet-cpp,majetideepak/parquet-cpp,wesm/parquet-cpp,majetideepak/parquet-cpp,apache/parquet-cpp