DOC: add contibutors to 1.2.0 release notes
test failure unrelated

```
=========================== short test summary info ============================
FAILED pandas/tests/io/test_gcs.py::test_to_csv_compression_encoding_gcs[zip-cp1251]
= 1 failed, 144014 passed, 3150 skipped, 1431 xfailed, 31 warnings in 3195.95s (0:53:15) =
```