_version.py: hush lgtm.com alert

This needs to be upstreamed into Versioneer, as it will disappear the next
time we upgrade.

src/wormhole_transit_relay/_version.py

@@ -495,7 +495,7 @@ def get_versions():
         # versionfile_source is the relative path from the top of the source
         # tree (where the .git directory might live) to this file. Invert
         # this to find the root from __file__.
-        for i in cfg.versionfile_source.split('/'):
+        for _ in cfg.versionfile_source.split('/'):
             root = os.path.dirname(root)
     except NameError:
         return {"version": "0+unknown", "full-revisionid": None,