Update changelog for 1.3.0 release
Update changelog for 1.3.0 release

Change-Id: Iab3060c3e2e29873c3e576c2c9232d3afdd37cd7

techoe/ceres-solver,techoe/ceres-solver,DougFirErickson/ceres-solver,ikoruk/ceres-solver,whuaegeanse/ceres-solver,pritasam/ceres-solver,whuaegeanse/ceres-solver,arnaudgelas/ceres-solver,timfel/ceres-bin,whuaegeanse/ceres-solver,whuaegeanse/ceres-solver,kartikkumar/ceres-solver,timfel/ceres-bin,stonier/ceres_solver,kartikkumar/ceres-solver,entylop/ceres-solver,ikoruk/ceres-solver,ysonggit/ceres-solver,kartikkumar/ceres-solver,entylop/ceres-solver,caomw/ceres-solver,timfel/ceres-bin,stonier/ceres_solver,ikoruk/ceres-solver,vedanshu95/ceres-solver,techoe/ceres-solver,DougFirErickson/ceres-solver,jmwalls/ceres-solver-fork,jmwalls/ceres-solver-fork,ysonggit/ceres-solver,arnaudgelas/ceres-solver,ysonggit/ceres-solver,kartikkumar/ceres-solver,vedanshu95/ceres-solver,DougFirErickson/ceres-solver,entylop/ceres-solver,timfel/ceres-bin,jmwalls/ceres-solver-fork,ysonggit/ceres-solver,entylop/ceres-solver,pritasam/ceres-solver,stonier/ceres_solver,ikoruk/ceres-solver,arnaudgelas/ceres-solver,ikoruk/ceres-solver,vedanshu95/ceres-solver,DougFirErickson/ceres-solver,caomw/ceres-solver,jmwalls/ceres-solver-fork,caomw/ceres-solver,pritasam/ceres-solver,stonier/ceres_solver