[Do not merge] Implement the "update" feature.

[Steap]

This still requires:

• testing
• updating the required version of upt in setup.cfg

[Steap]

This pull request is mostly a call for testing :) @reneeotten @mojca

This change requires changes in upt itself, and these changes have not been released. The following script creates a virtual env in /tmp/.upt-venv and lets you use the latest upt and upt-macports (== this patch on top of master). Just use upt-update.sh as you would use upt:

$ upt-update.sh package -f pypi -b macports -u nwdiag
Running /tmp/.upt-venv/bin/upt package -f pypi -b macports -u nwdiag
[INFO    ] [Backend] Checking MacPorts tree for port py-nwdiag
[INFO    ] [Backend] Current MacPorts Version for py-nwdiag is 1.0.4
[INFO    ] [Backend] Updating nwdiag from 1.0.4 to 2.0.0

$ git diff
diff --git a/python/py-nwdiag/Portfile b/python/py-nwdiag/Portfile
index 50257bc15c4..90471d3bcd6 100644
--- a/python/py-nwdiag/Portfile
+++ b/python/py-nwdiag/Portfile
@@ -4,7 +4,7 @@ PortSystem          1.0
 PortGroup           python 1.0

 name                py-nwdiag
-version             1.0.4
+version             2.0.0
 revision            0
 categories-append   graphics
 platforms           darwin
@@ -23,13 +23,17 @@ master_sites        pypi:n/nwdiag/

 distname            nwdiag-${version}

-checksums           rmd160  151f22c058337febc8ef93996b7abbed823ef83e \
-                    sha256  002565875559789a2dfc5f578c07abdf44269c3f7cdf78d4809bdc4bdc2213fa \
-                    size    2652472
+checksums           rmd160  769b1298ca1a9043e77b034476cb1657cf209f74 \
+                    sha256  5cd7fafd6085cd762ca9171234d07d2a33c6e81f5c66a1b233992e76300d74e2 \
+                    size    7751634

 if {${name} ne ${subport}} {
-    depends_lib-append  port:py${python.version}-setuptools \
-                        port:py${python.version}-blockdiag
+    depends_lib-append  port:py${python.version}-blockdiag

     livecheck.type      none
 }
+#TODO: Move this
+depends_test-append port:py${python.version}-flake8 \
+                    port:py${python.version}-flake8-coding \
+                    port:py${python.version}-flake8-copyright \
+                    port:py${python.version}-flake8-isort

[reneeotten]

thanks @Steap - I will take a closer look at this in the next few days!