style: simplify init

Signed-off-by: Jan Kowalleck <[email protected]>

Author: jkowalleck

cyclonedx/model/vulnerability.py

@@ -977,7 +977,7 @@ def __init__(
         self.published = published
         self.updated = updated
         self.credits = credits
-        self.tools = tools or ToolsRepository()  # type:ignore[assignment]  # type:ignore[assignment]
+        self.tools = tools or []  # type:ignore[assignment]
         self.analysis = analysis
         self.affects = affects or []  # type:ignore[assignment]
         self.properties = properties or []  # type:ignore[assignment]