Added "LICENSE.txt" and "README.txt" as recognized filenames
Added "LICENSE.txt" and "README.txt" as recognized filenames

The webstack packages (HttpCommon, Meddle, etc) have license files named "LICENSE.txt", so they don't currently get detected by PackageEvaluator. This fixes that.
simonster/PackageEvaluator.jl,IainNZ/PackageEvaluator.jl,aviks/PackageEvaluator.jl,IainNZ/PackageEvaluator.jl,JuliaCI/PackageEvaluator.jl,ScottPJones/PackageEvaluator.jl,tkelman/PackageEvaluator.jl,ScottPJones/PackageEvaluator.jl,Jeblist/PackageEvaluator.jl,phobon/PackageEvaluator.jl,aviks/PackageEvaluator.jl,jiahao/PackageEvaluator.jl,tkelman/PackageEvaluator.jl,ScottPJones/PackageEvaluator.jl,phobon/PackageEvaluator.jl,Jeblist/PackageEvaluator.jl,simonster/PackageEvaluator.jl,jiahao/PackageEvaluator.jl,JuliaCI/PackageEvaluator.jl,timholy/PackageEvaluator.jl,timholy/PackageEvaluator.jl,JuliaCI/PackageEvaluator.jl,jiahao/PackageEvaluator.jl,IainNZ/PackageEvaluator.jl