sprintf deprecated

sprintf is deprecated on macos clang.

"Use snprintf if available as some compilers (clang 14.0) issue deprecation warnings for sprintf"

sprintf appears in these files:

```
libs/format/benchmark/bench_format.cpp:// bench_variants.cc : do the same task, with sprintf, stream, and format
libs/format/benchmark/bench_format.cpp: // Check that sprintf is Unix98 compatible on the platform :
libs/format/benchmark/bench_format.cpp:// (e.g., it expects sprintf to be POSIX compliant)
libs/format/benchmark/bench_format.cpp:#include // sprintf
libs/format/benchmark/bench_format.cpp: sprintf(buf, fstring.c_str(), arg1, arg2, arg3);
libs/format/benchmark/bench_format.cpp: sprintf(buf, fstring.c_str(), arg1, arg2, arg3);
```