Merge remote-tracking branch 'ruslo/master'
Update 'utf8' to v3.1.1 (#223)
Update testing documentation links (#219)
Update testing documentation links (#217)
HunterGate(
URL "https://github.com/cpp-pm/hunter/archive/v0.23.261.tar.gz"
SHA1 "1540dad7b97c849784a09e8c452ba811c9f71ba2"
)