Use Swift 5.7.0. (#8501)
Use Swift 5.7.0. (#8501)

Swift 5.4.2 was released back in June 2021.

Co-authored-by: jonathanmetzman <1cd2180ab9a3022d8b6aea1aa47f4627a8a95d43@users.noreply.github.com>
google/oss-fuzz,skia-dev/oss-fuzz,google/oss-fuzz,google/oss-fuzz,google/oss-fuzz,skia-dev/oss-fuzz,skia-dev/oss-fuzz,skia-dev/oss-fuzz,skia-dev/oss-fuzz,google/oss-fuzz,google/oss-fuzz,google/oss-fuzz,skia-dev/oss-fuzz,google/oss-fuzz,skia-dev/oss-fuzz,google/oss-fuzz,skia-dev/oss-fuzz,google/oss-fuzz,skia-dev/oss-fuzz,skia-dev/oss-fuzz,google/oss-fuzz,skia-dev/oss-fuzz