update binder links to 0.15.2
update binder links to 0.15.2

twosigma/beakerx,jpallas/beakerx,twosigma/beaker-notebook,twosigma/beaker-notebook,jpallas/beakerx,jpallas/beakerx,twosigma/beakerx,jpallas/beakerx,twosigma/beaker-notebook,twosigma/beaker-notebook,jpallas/beakerx,twosigma/beakerx,twosigma/beakerx,twosigma/beaker-notebook,twosigma/beakerx,twosigma/beakerx,jpallas/beakerx