Add color to output of XEP validation script

[guusdk]

Github workflows tend to be verbose. This can make it difficult to determine why a failure occurs.

To help identify causes for validation failures, the output of the XEP-0001 conformance script should have a bit of color to highlight the important bits (Github supports this).

The output will depend on the terminal used to display the content, but will look somewhat like this:

It has:

• newlines before and after the results of each check
• a red-ish color for failed checks
• a green-ish color for passed checks
• a blue-ish color for informational messages