Use path.name directly w/o assignment

Apply suggestions from code review

Co-authored-by: Ben Mares <services-git-throwaway1@tensorial.com>

conda_lock/conda_solver.py

@@ -561,7 +561,6 @@ def fake_conda_environment(
             channel = urlunsplit(
                 (url.scheme, url.hostname, str(path.parent), None, None)
             )
-            file_name = path.name
             while path.suffix in {".tar", ".bz2", ".gz", ".conda"}:
                 path = path.with_suffix("")
             build = path.name.split("-")[-1]
@@ -578,7 +577,7 @@ def fake_conda_environment(
                 "build_number": build_number,
                 "version": dep.version,
                 "subdir": path.parent.name,
-                "fn": file_name,
+                "fn": path.name,
                 "depends": [f"{k} {v}".strip() for k, v in dep.dependencies.items()],
             }
             # mamba requires these to be stringlike so null are not allowed here