add swift compatibility in README
add swift compatibility in README

HyprMXMobile/OHHTTPStubs,HyprMXMobile/OHHTTPStubs,tarbrain/OHHTTPStubs,danielctull-forks/OHHTTPStubs,tarbrain/OHHTTPStubs,danielctull-forks/OHHTTPStubs,HyprMXMobile/OHHTTPStubs,danielctull-forks/OHHTTPStubs,danielctull-forks/OHHTTPStubs,tarbrain/OHHTTPStubs,tarbrain/OHHTTPStubs,HyprMXMobile/OHHTTPStubs