Bump memmap2 from 0.3.0 to 0.3.1 in /src/agent

Bumps [memmap2](https://github.com/RazrFalcon/memmap2-rs) from 0.3.0 to 0.3.1.
- [Release notes](https://github.com/RazrFalcon/memmap2-rs/releases)
- [Changelog](https://github.com/RazrFalcon/memmap2-rs/blob/master/CHANGELOG.md)
- [Commits](RazrFalcon/memmap2-rs@v.0.3.0...v0.3.1)

---
updated-dependencies:
- dependency-name: memmap2
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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