Add support for Float32 coordinates

[eliascarv]

The Shapefile specification requires coordinate values ​​to be in Float64:

This PR adds missing coordinate conversions to Float64, thus adding support for writing geometries with Float32 coordinates:

main:

julia> using Shapefile, GeoJSON

julia> geojson = GeoJSON.read("countries.geojson")
FeatureCollection with 177 Features

julia> Shapefile.write("countries.shp", geojson)
┌ Warning: Could not convert CRS of type `GeoFormatTypes.EPSG{1}` to `GeoFormatTypes.ESRIWellKnownText{GeoFormatTypes.CRS}`.  `using ArchGDAL` may load the necessary `Base.convert` method.  The CRS WILL NOT BE SAVED as a .prj file.
└ @ Shapefile ~/Documentos/JuliaDev/Shapefile.jl/src/writer.jl:26
ERROR: AssertionError: rec_bytes == calc_rec_bytes
Stacktrace:
 [1] write(path::String, o::Shapefile.Writer; force::Bool)
   @ Shapefile ~/Documentos/JuliaDev/Shapefile.jl/src/writer.jl:213
 [2] write
   @ ~/Documentos/JuliaDev/Shapefile.jl/src/writer.jl:93 [inlined]
 [3] write(path::String, obj::GeoJSON.FeatureCollection{2, Float32})
   @ Shapefile ~/Documentos/JuliaDev/Shapefile.jl/src/writer.jl:269
 [4] top-level scope
   @ REPL[6]:1

PR:

julia> using Shapefile, GeoJSON

julia> geojson = GeoJSON.read("countries.geojson")
FeatureCollection with 177 Features

julia> Shapefile.write("countries.shp", geojson)
┌ Warning: Could not convert CRS of type `GeoFormatTypes.EPSG{1}` to `GeoFormatTypes.ESRIWellKnownText{GeoFormatTypes.CRS}`.  `using ArchGDAL` may load the necessary `Base.convert` method.  The CRS WILL NOT BE SAVED as a .prj file.
└ @ Shapefile ~/Documentos/JuliaDev/Shapefile.jl/src/writer.jl:26
180812

julia> Shapefile.Table("countries.shp")
Shapefile.Table{Union{Missing, Shapefile.Polygon}} with 177 rows and the following 3 columns:

geometry, COUNTRY, REGION

Link to download the countries.geojson file: https://github.com/JuliaEarth/geospatial-data-science-with-julia/blob/main/data/countries.geojson

[rafaqz]

Thanks! this looks good to me

[eliascarv]

Would it be possible to release a patch after merging the PR please?