bcbio-gff: `pkg_resources` deprecated

setuptools 67 deprecated `pkg_resources` and it was removed in version 82.
This breaks the build of bcbio-gff-0.7.1:
```
Traceback (most recent call last):
  File "/tmp/biology/py-bcbio-gff/work/bcbio-gff-0.7.1/distribute_setup.py", line 146, in use_setuptools
    import pkg_resources
ModuleNotFoundError: No module named 'pkg_resources'
```
