config.json: Deprecate all base-conversions (#432)
config.json: Deprecate all base-conversions (#432)

We added all-your-base in #404 but forgot to deprecate all the
base-conversion exercises!

According to https://github.com/exercism/x-common/issues/279,
all-your-base is meant to deprecate all of these.
exercism/xgo,robphoenix/exercism-go,leenipper/xgo,exercism/xgo,robphoenix/exercism-go,leenipper/xgo