build(deps): bump the submodules group with 3 updates

Bumps the submodules group with 3 updates: [bgfx](https://github.com/bkaradzic/bgfx), [bx](https://github.com/bkaradzic/bx) and [bimg](https://github.com/bkaradzic/bimg).


Updates `bgfx` from `23baae9` to `7a70927`
- [Commits](bkaradzic/bgfx@23baae9...7a70927)

Updates `bx` from `d858859` to `eda3839`
- [Commits](bkaradzic/bx@d858859...eda3839)

Updates `bimg` from `3af74f3` to `a1a2ae3`
- [Commits](bkaradzic/bimg@3af74f3...a1a2ae3)

---
updated-dependencies:
- dependency-name: bgfx
  dependency-version: 7a70927
  dependency-type: direct:production
  dependency-group: submodules
- dependency-name: bx
  dependency-version: eda38395ddfdeba08c46653b93b8d5bb21f2c863
  dependency-type: direct:production
  dependency-group: submodules
- dependency-name: bimg
  dependency-version: a1a2ae3c129d8c33e765eecd91801bffd985c317
  dependency-type: direct:production
  dependency-group: submodules
...

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Author: dependabot[bot]