Add valuetype to example config.yml

[ilario]

This changes the out put of the examples from:

# HELP example_global_value Example of a top-level global value scrape in the json
# TYPE example_global_value untyped
example_global_value{environment="beta",location="planet-mars"} 1234
...

to

# HELP example_global_value Example of a top-level global value scrape in the json
# TYPE example_global_value counter
example_global_value{environment="beta",location="planet-mars"} 1234
...

Note that "untyped" has been replaced by the valuetype indicated in the example.