Describe the bug
What count in rust project, the Cargo.lock file also counted.

Like: https://github.com/cgag/loc

To Reproduce

1. In Any cargo based rust project, run scc
2. The result show Cargo Lock lines.

Expected behavior
Cargo.lock is auto generated file, should not be counted.

Desktop (please complete the following information):

• OS: macOS 10.15.5
• scc version 2.13.0