Pin packages and add lockfile for reproducible builds

[ms1111]

Description

To ensure reproducibility and minimize susceptibility to supply chain attacks, use a lock file for dependencies. As suggested in https://github.com/GameBridgeAI/ts_serialize/pull/166#issuecomment-3339625062

Using lockfile for deno v2 only.

For v1, it'd be a different lockfile format, and given it's only a few, pinned, standard packages, the risk of using unpinned transitive dependencies is low, and I figure the v1 build will go away at some point.

Things to look at

• [ ] Test coverage
• [ ] Code Style
• [ ] Documentation (README.md, CHANGELOG.md, etc..)

[hardy613]

and I figure the v1 build will go away at some point.

yea, we can discuss that deprecation, although I hear v1 is still in use - so we'll need ot be clear about it somehow