Feature request: support subdir regex?

In KernelFunctions.jl we use separate project environments for all examples. The examples are contained in directories `examples/first_example/`, `examples/second_example/` etc. It seems currently one has to add all directories to CompatHelper.yml manually. It would be very convenient if one could just use a regex such as `examples/*/` (and maybe even `examples/**/` for recursive subdirectories).

Start by tracing how CompatHelper.yml currently lists project directories and how the examples in KernelFunctions.jl are represented. Define the matching behavior for `examples/*/` and recursive `examples/**/` patterns, then add coverage showing that matching example environments are discovered without manual entries.

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