Add example of enable-versioned-regex

[gregsdennis]

The readme shows usage of enable-versioned-regex, but it doesn't explain what this does or why it should be used.

Is the property required? If not, what is the default if omitted?

[aarikpokras]

According to action.yml,

  enable-versioned-regex:
    description: 'Controls if versioned regex templates are being used'
    required: true

In other words, it is required. I have it set to zero.