Bump version to 3.1
Bump version to 3.1

ruisebastiao/FluentValidation,roend83/FluentValidation,cecilphillip/FluentValidation,GDoronin/FluentValidation,mgmoody42/FluentValidation,IRlyDontKnow/FluentValidation,pacificIT/FluentValidation,olcayseker/FluentValidation,robv8r/FluentValidation,roend83/FluentValidation,regisbsb/FluentValidation,glorylee/FluentValidation,deluxetiky/FluentValidation