HDF5.jl with vector of tuples of strings

@mkitti I just stumbled on another similar string related issue. If one tries to write a Vector{@NamedTuple...} where at least one type is a string, the writing fails. This is on v0.17.3. using HDF5 arr = [ (;A="A",B=1), (;A="A",B=2) ] h5write("test.h5", "test", arr) ERROR: ArgumentError: Could not convert non-bitstype @NamedTuple{A::String, B::Int64} to @NamedTuple{A::HDF5.FixedString{1, 0}, B::Int64} for writing to HDF5. Consider implementing convert(::Type{@NamedTup...