GHSA-ppjr-267j-5p9x: NULL pointer derefernce in `stb_image`

A bug in error handling in the stb_image C library could cause a NULL pointer dereference when attempting to load an invalid or unsupported image file. This is fixed in version 0.2.5 and later of the stb_image Rust crate, by patching the C code to correctly handle NULL pointers.

Thank you to GitHub user 0xdd96 for finding and fixing this vulnerability.