Update kerl to accept new version numbering scheme since 17.0-rc1

* Change get_releases() to accept the new naming scheme of
  `otp_src_MAJOR.MINOR.PATCH.tar.gz`, where MAJOR, MINOR, PATCH
  are all decimal letters and some additional letters in
  `[-0-9A-Za-z_.]` (see OTP-11615 on otp_src_17.0-rc1.tar.gz)