Update Eigen to 6e067669fbba

Last commit: https://bitbucket.org/eigen/eigen/commits/6e067669fbba47aae231dbd86eac5e8c7c42a782

PiperOrigin-RevId: 267216378
Change-Id: I80ca3306195ce8a3f8028c8655eee7e821db7241
8 files changed