Release announcements for DataFrames.jl

Thanks. One more quesiton. using first(df,n) instead of head(df,6) gives this warning.

first(data,6)

Warning: In the future eachcol will have names argument set to false by default
│   caller = getmaxwidths(::DataFrame, ::UnitRange{Int64}, ::UnitRange{Int64}, ::Symbol) at show.jl:105
└ @ DataFrames C:\Users\chatura\.julia\packages\DataFrames\5Rg4Y\src\abstractdataframe\show.jl:105