Update eip-197.md

Author: chriseth

EIPS/eip-197.md

@@ -136,3 +136,7 @@ Implementations are available here:
  - [libff](https://github.com/scipr-lab/libff/blob/master/libff/algebra/curves/alt_bn128/alt_bn128_g1.hpp) (C++)
  - [bn](https://github.com/zcash/bn/blob/master/src/groups/mod.rs) (Rust)
  - [Python](https://github.com/ethereum/py_pairing/blob/master/py_ecc/bn128/bn128_pairing.py)
+
+## Copyright
+
+Copyright and related rights waived via [CC0](https://creativecommons.org/publicdomain/zero/1.0/).