py-requests-cache: add py37 subport

- use default PyPI livecheck

python/py-requests-cache/Portfile

@@ -11,7 +11,7 @@ platforms           darwin
 license             BSD
 supported_archs     noarch
 
-python.versions     27 34 35 36
+python.versions     27 34 35 36 37
 
 maintainers         nomaintainer
 
@@ -26,6 +26,4 @@ if {${name} ne ${subport}} {
                         port:py${python.version}-requests
 
     livecheck.type      none
-} else {
-    livecheck.type      pypi
 }