## Changes
Semantics for merging two instances of `config.Value`:
* Merging x with nil or nil with x always yields x
* Merging maps a and b means entries from map b take precedence
* Merging sequences a and b means concatenating them
These are the same semantics that we use today when calling into mergo
in `bundle/config`.
## Tests
Unit tests pass.
Pieter Noordhuis