We just did a minor bug fix to error code in the `amounts` module. This
change did not effect the public API but improved the display of two
error types from that module.
In preparation for doing a point release bump the version number and add
a changelog entry.
In preparation for the initial release add a changelog. Note the version
number is already set to `v0.1.0` and this does not conflict with the
release currently on crates.io `v0.0.0`.