drops python2 dependency and uses python3

mono/.signature

@@ -1,5 +1,5 @@
 untrusted comment: verify with /etc/ports/contrib.pub
-RWSagIOpLGJF360hGlSo3EI7JWSH1EwzkwYGgRZTLjcfDk8PcFJ/+lvGm323QXUEpJnXEthe+Izt+NkvVYQxu/fkPqNwhCJqyQo=
-SHA256 (Pkgfile) = a413ec977ef000e9f4e2153b0ce4f06d038e126a4d551bb0319ac49340ad4d70
+RWSagIOpLGJF36jtXJqbBNK4dPql8tePQACUssusMT/q0ZEZSgeADLi/O0eXA2B+Xq+/qy7OfgFJ3cw/XWj3rNKhCYU61KKDeA4=
+SHA256 (Pkgfile) = c31c609cb1c2d5ae19bb14036878bf62cdf4b5a737f96cb3f7fb27d62cabff6d
 SHA256 (.footprint) = dfcd9ebd7a4063061ba5699409f9f6c86fc3e3b1f7476ebe165e2adc6b06e525
 SHA256 (mono-6.8.0.105.tar.xz) = 578799c44c3c86a9eb5daf6dec6c60a24341940fd376371956d4a46cf8612178

mono/Pkgfile

@@ -1,13 +1,13 @@
 # Description: Cross platform, open source .NET framework
-# URL: http://www.mono-project.com
+# URL: https://www.mono-project.com
 # Maintainer: Tim Biermann, tbier at posteo dot de
 # Packager: poq <jbloomfield at live dot com>
-# Depends on: python cmake zlib
+# Depends on: cmake python3 zlib
 
 name=mono
 version=6.8.0.105
 release=1
-source=(http://download.mono-project.com/sources/$name/$name-$version.tar.xz)
+source=(https://download.mono-project.com/sources/$name/$name-$version.tar.xz)
 
 build() {
   cd $name-$version
@@ -17,7 +17,7 @@ build() {
     --with-mcs-docs=no \
     --disable-crash-reporting \
     --disable-nls
-  make
+  PYTHON=python3 make
   make DESTDIR=$PKG install
   rm -fr $PKG/usr/share/locale
   find $PKG \( -iname "*README*" \