When the package was last modified, the version wasn't released; an
unreleased commit was used. This is no longer necessary. The tag only
differs in the version number from the commit that was being used
before.
* gnu/packages/python-xyz.scm (python-binwalk): Use a released tag
(v2.2.0).
Co-authored-by: Vincent Legoll <vincent.legoll@gmail.com>