gnu: poetry: Remove redundant input.

* gnu/packages/python-xyz.scm (poetry)[propagated-inputs]: Remove PYTHON-PATHLIB2.

gnu/packages/python-xyz.scm

@@ -10600,7 +10600,6 @@ (define-public poetry
        ("python-html5lib" ,python-html5lib)
        ("python-jsonschema" ,python-jsonschema)
        ("python-msgpack" ,python-msgpack)
-       ("python-pathlib2" ,python-pathlib2)
        ("python-pkginfo" ,python-pkginfo)
        ("python-pyparsing" ,python-pyparsing)
        ("python-pyrsistent" ,python-pyrsistent)