build(deps): bump the submodules group with 3 updates (#252)

Bumps the submodules group with 2 updates in the / directory: [bgfx](https://github.com/bkaradzic/bgfx) and [bx](https://github.com/bkaradzic/bx).


Updates `bgfx` from `409fbc5` to `7e5bb54`
- [Commits](409fbc5d14...7e5bb54a3e)

Updates `bx` from `3d53a4a` to `296dfb2`
- [Commits](3d53a4abaa...296dfb202b)

---
updated-dependencies:
- dependency-name: bgfx
  dependency-type: direct:production
  dependency-group: submodules
- dependency-name: bx
  dependency-type: direct:production
  dependency-group: submodules
...

Signed-off-by: dependabot[bot] <support@github.com>

cmake/bgfx/3rdparty/spirv-opt.cmake

@@ -74,6 +74,8 @@ file(
 	${SPIRV_TOOLS}/source/text.h
 	${SPIRV_TOOLS}/source/text_handler.cpp
 	${SPIRV_TOOLS}/source/text_handler.h
+	${SPIRV_TOOLS}/source/to_string.cpp
+	${SPIRV_TOOLS}/source/to_string.h
 	${SPIRV_TOOLS}/source/util/bit_vector.cpp
 	${SPIRV_TOOLS}/source/util/bit_vector.h
 	${SPIRV_TOOLS}/source/util/bitutils.h