error import from safetydb: Invalid version

I enabled the safetydb importer locally by uncommenting it. When I run that importer, an error occured:
```
File "/home/sify/Source/vulnerablecode/vulnerabilities/importers/safety_db.py", line 101, in updated_advisories
impacted_purls, resolved_purls = categorize_versions(
File "/home/sify/Source/vulnerablecode/vulnerabilities/importers/safety_db.py", line 147, in categorize_versions
vurl_specs.append(VersionSpecifier.from_scheme_version_spec_string("pypi", version_spec))
File "/home/sify/Source/vulnerablecode/venv/lib64/python3.9/site-packages/univers/version_specifier.py", line 137, in from_scheme_version_spec_string
rng = VersionRange(version_range, scheme)
File "/home/sify/Source/vulnerablecode/venv/lib64/python3.9/site-packages/univers/version_range.py", line 42, in __init__
self.version = version_class(self.version)
File "/home/sify/Source/vulnerablecode/venv/lib64/python3.9/site-packages/univers/versions.py", line 68, in __init__
self.validate(version_string)
File "/home/sify/Source/vulnerablecode/venv/lib64/python3.9/site-packages/univers/versions.py", line 76, in validate
raise InvalidVersion(f"Invalid version: '{version_string}'")
univers.versions.InvalidVersion: Invalid version: '0.28.3.gfm.12'
Failure to import data from safetydb. Continuing...
CommandError: 1 failed!: safetydb
```