Fix `ERR_CHILD_PROCESS_STDIO_MAXBUFFER` error

[dnicolson]

This pull request attempts to fix the RangeError [ERR_CHILD_PROCESS_STDIO_MAXBUFFER]: stderr maxBuffer length exceeded. Alternatively, exec could be replaced with spawn as suggested in https://github.com/tom-s/clap-detector/issues/21#issuecomment-1024965201 and implemented in https://github.com/131/clap-trigger/blob/b6f890e/index.js#L80-L104, this would require more significant changes though.