Update spirv-tools to fix gcc warning

[Jake-Shadle]

Encountered a warning (which fails the build due to warnings as errors) for spirv-tools, so this updates to use the fix I added.

    cargo:warning=spirv-tools/source/diagnostic.cpp: In function ‘spv_diagnostic_t* spvDiagnosticCreate(spv_position, const char*)’:
    cargo:warning=spirv-tools/source/diagnostic.cpp:40:10: error: ‘char* strncpy(char*, const char*, size_t)’ specified bound depends on the length of the source argument [-Werror=stringop-truncation]
    cargo:warning=   40 |   strncpy(diagnostic->error, message, length);
    cargo:warning=      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    cargo:warning=spirv-tools/source/diagnostic.cpp:31:25: note: length computed here
    cargo:warning=   31 |   size_t length = strlen(message) + 1;
    cargo:warning=      |                   ~~~~~~^~~~~~~~~
    cargo:warning=cc1plus: all warnings being treated as errors
    exit status: 1