py-cheroot: update to 6.5.4; add python 37; add dependencies

python/py-cheroot/Portfile

@@ -4,8 +4,7 @@ PortSystem          1.0
 PortGroup           python 1.0
 
 name                py-cheroot
-# Newer versions require setuptools_scm_git_archive not in macports
-version             5.8.3
+version             6.5.4
 categories-append   www
 platforms           darwin
 supported_archs     noarch
@@ -21,14 +20,20 @@ homepage            https://pypi.python.org/pypi/${python.rootname}
 distname            ${python.rootname}-${version}
 master_sites        pypi:[string index ${python.rootname} 0]/${python.rootname}
 
-checksums           rmd160  0f5cc2998d3d68162fe2e1b84e16f527d663f064 \
-                    sha256  5c0531fd732700b1fb3e6e7079dc3aefbdf29e9136925633d93f009cb87d70a3
+checksums           rmd160  3ce30606c0f1808544c4dc0305a9255b9bdffc1f \
+                    sha256  beb8eb9eeff5746059607e81b72efd6f4ca099111dc13f8961ae9e4f63f7786b \
+                    size    81067
 
-python.versions     27 34 35 36
+python.versions     27 34 35 36 37
 
 if {${name} ne ${subport}} {
-    depends_build-append    port:py${python.version}-setuptools_scm
-    depends_lib-append      port:py${python.version}-six
+    depends_build-append    port:py${python.version}-setuptools_scm_git_archive
+    depends_lib-append      port:py${python.version}-more-itertools \
+                            port:py${python.version}-six
+
+    if {${python.version} eq 27} {
+        depends_lib-append  port:py${python.version}-backports-functools_lru_cache
+    }
 
     livecheck.type  none
 } else {