Ignore untested exception

src/nox_poetry/sessions.py

@@ -67,7 +67,7 @@ def to_constraint(requirement_string: str, line: int) -> Optional[str]:
 
     try:
         requirement = Requirement(requirement_string)
-    except InvalidRequirement as error:
+    except InvalidRequirement as error:  # pragma: no cover
         raise RuntimeError(f"line {line}: {requirement_string!r}: {error}") from error
 
     if not (requirement.name and requirement.specifier):