ShareDB Milestone MongoDB Adapter

sharedb-milestone-mongo is a database adapter for ShareDB that specifically targets MongoDB, enabling the use of 'milestone snapshots' to optimize the `connection.fetchSnapshot` method. These snapshots create specific points in time from which a smaller number of operations can be applied to reconstruct the requested document version, significantly improving performance for frequently accessed older versions. The current stable version is 2.1.0, and the package demonstrates a consistent release cadence, frequently updating to support newer versions of both Node.js (dropping older LTS versions) and its core dependencies, `mongodb` and `sharedb`. It stores these milestones in a dedicated `m_COLLECTION` in the MongoDB database, configurable for saving intervals or complex middleware-based logic.