Update Pip log output test assertion after PyPI metadata backfill

Pip prints slightly different log output depending on whether the
package being installed has the new PEP 658 `.metadata` file available
on PyPI.

Until now, only packages uploaded to PyPI since the feature was
implemented had this metadata generated by PyPI, however, the metadata
file has now been backfilled for older packages too:
pypi/warehouse#8254 (comment)

As a result, the Pip support log output assertion needs updating for
the new output, to fix CI on `main`:
https://github.com/heroku/heroku-buildpack-python/actions/runs/8138313649/job/22238825835?pr=1545#step:5:479

GUS-W-15172805.

Author: edmorley

spec/hatchet/pip_spec.rb

@@ -70,6 +70,7 @@
           remote:        Collecting six \\(from -r requirements.txt \\(line 2\\)\\)
           remote:          Downloading six-.*
           remote:        Downloading urllib3-.*
+          remote:        Downloading six-.*
           remote:        Installing collected packages: urllib3, six
           remote:        Successfully installed six-.* urllib3-.*
         REGEX