Update CHANGELOG.

Change-Id: I55cb72f1866254dd6456259090b121d983bf9260
Release 1.2.0.

Change-Id: I0afcece6b69185014bdd8f501ea06a7919f3c3a4
Bump version after release.

Change-Id: I3712b74ed965d94a00eb375c52f98eceec0a09ed