Bump src/3dparty/JNet from 45a2d05 to 781a50b

Bumps [src/3dparty/JNet](https://github.com/masesgroup/JNet) from `45a2d05` to `781a50b`.
- [Release notes](https://github.com/masesgroup/JNet/releases)
- [Commits](masesgroup/JNet@45a2d05...781a50b)

---
updated-dependencies:
- dependency-name: src/3dparty/JNet
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>