Handle absolute sources path read from the lockfile

* Addressing the inconsistency with the absolute source paths introduced in #175 and noticed in #229.

conda_lock/conda_lock.py

@@ -929,7 +929,9 @@ def run_lock(
             lock_content = parse_conda_lock_file(lockfile_path)
             # reconstruct native paths
             locked_environment_files = [
-                pathlib.Path(
+                pathlib.Path(p)
+                if pathlib.Path(p).is_absolute
+                else pathlib.Path(
                     pathlib.PurePosixPath(lockfile_path).parent
                     / pathlib.PurePosixPath(p)
                 )