notary client fails on Windows when GUN contains a port

[cfiderer]

Running notary on a GUN that contains a port number (e.g. the 443 in docker.io:443/library/ubuntu) on Windows fails because the colon is an invalid character in a directory name:

notary -v -D -s https://notary.docker.io lookup docker.io:443/library/ubuntu 18.04
[37mDEBU[0m[0000] Configuration file not found, using defaults
[37mDEBU[0m[0000] Using the following trust directory: C:\Users\d041725\.notary

* fatal: mkdir C:\Users\cfiderer\.notary\tuf\docker.io:443: The directory name is invalid.

This makes it impossible to run the notary client with private registries that use non-standard ports.

[zillani]

any update on this, same problem :(