Environment variables within config.yml

It seems that the config.yml is not pre-processed for environment variable substitution so the following within config.yml will not work


This type of basic isolation support would be rather useful when using self-defined runners as it will mean that reused config blocks across projects or configs that get run across different branches do not trip each other up. Reused working directories just cause git errors as and when.

There seems to have been talk of such a feature a few years back when the 2.0 config.yml format was introduced as it seems that removed such a feature, but I have not found any recent updates.