Fix Snowflake connector MemoryError for ffi.callback() on Apple Silicon
If `import snowflake.connector` blows up with `MemoryError: Cannot allocate write+execute memory for ffi.callback()` on an M1 Mac under conda, your cffi build is the culprit. Run `conda install "cffi >= 1.15.1=*_3"` (build 3 from conda-forge carries the upstream fix) and restart. Multiple users on t…