message: Added Golden-section search also to Readme
diff: @@ -65,6 +65,7 @@ remain future plans.
  - [SR1-TrustRegion](https://argmin-rs.github.io/argmin/argmin/solver/quasinewton/sr1_trustregion/struct.SR1TrustRegion.html)
  - [Gauss-Newton method](https://argmin-rs.github.io/argmin/argmin/solver/gaussnewton/gaussnewton_method/struct.GaussNewton.html)
  - [Gauss-Newton method with linesearch](https://argmin-rs.github.io/argmin/argmin/solver/gaussnewton/gaussnewton_linesearch/struct.GaussNewtonLS.html)
  +- [Golden-section search](https://argmin-rs.github.io/argmin/argmin/solver/goldensectionsearch/struct.GoldenSectionSearch.html)
  - [Landweber iteration](https://argmin-rs.github.io/argmin/argmin/solver/landweber/struct.Landweber.html)
  - [Brent's method](https://argmin-rs.github.io/argmin/argmin/solver/brent/index.html)
  - [Nelder-Mead method](https://argmin-rs.github.io/argmin/argmin/solver/neldermead/struct.NelderMead.html)
  