lcms2: update to 2.19.1

graphics/lcms2/Portfile

@@ -2,9 +2,10 @@
 
 PortSystem              1.0
 PortGroup               muniversal 1.0
+PortGroup               github 1.0
 
 name                    lcms2
-version                 2.19
+github.setup            mm2 Little-CMS 2.19.1 lcms
 revision                0
 worksrcdir              lcms2-${version}
 categories              graphics
@@ -22,12 +23,14 @@ long_description        LCMS is the Little Color Management System, a portable \
 
 homepage                https://littlecms.com/
 
+distname                ${name}-${version}
+github.tarball_from     releases
 master_sites            sourceforge:project/lcms/lcms/${version}/ \
                         ${homepage}
 
-checksums           rmd160  afdedef0b0cfd7860a63d6d9f89e68807dea7949 \
-                    sha256  49e7e134e4299733dd0eda434fa468997a28ab3d33fa397c642b03644f552216 \
-                    size    5726199
+checksums           rmd160  e89db66cf9e9396f58948edeaf4d7e64e6d89075 \
+                    sha256  bfc54f7bab59fbc921012014a8032e4cba4abd46db47d46b76416a8c0b2815c8 \
+                    size    5728743
 
 # Disable use of obsolete 'register' storage class; causes dependent build errors with newer compilers:
 # lcms2.h: error: ISO C++17 does not allow 'register' storage class specifier [-Wregister]
@@ -46,6 +49,5 @@ if {[vercmp ${xcodeversion} 10.0] >= 0 && ${universal_possible} && [variant_isse
 test.run                yes
 test.target             check
 
-livecheck.type          regex
-livecheck.url           https://littlecms.com/tags/releases
-livecheck.regex         "Little CMS (\\d+(?:\\.\\d+)+)"
+# only allow numbers, to avoid pre-release versions
+github.livecheck.regex  {([0-9.]+)}