lens @6.1.14: Playwright does not support webkit on mac10.13

[ryandesign (Ryan Carsten Schmidt)]

lens fails to build on High Sierra and earlier.

​On 10.13:

Error: ERROR: Playwright does not support webkit on mac10.13

​On 10.12:

dyld: Symbol not found: _SecTrustEvaluateWithError
  Referenced from: /opt/local/var/macports/build/_opt_bblocal_var_buildworker_ports_build_ports_sysutils_lens/lens/work/lens-6.1.14/node_modules/esbuild-darwin-64/bin/esbuild
  Expected in: flat namespace

​On 10.9–10.11:

dyld: lazy symbol binding failed: Symbol not found: _clock_gettime
  Referenced from: /opt/local/var/macports/build/_opt_bblocal_var_buildworker_ports_build_ports_sysutils_lens/lens/work/lens-6.1.14/node_modules/@swc/core-darwin-x64/swc.darwin-x64.node (which was built for Mac OS X 10.13)
  Expected in: /usr/lib/libSystem.B.dylib

Please indicate in the Portfile that it requires 10.14 or later (perhaps ​using platforms).