SWIFT_VERSION '3.0' is unsupported, supported versions are: 4.0, 4.2, 5.0. (in t

今天写学习swift的时候遇到个错误，自己顺便记录一下，完整错误信息如下

SWIFT_VERSION '3.0' is unsupported, supported versions are: 4.0, 4.2, 5.0. (in target '')

去Build Setting中把Swift Language Version下改为Swift 4或者5即可