changed installation in README and docs

Author: nantonel

README.md

@@ -29,7 +29,7 @@ It supports complex variables as well.
 To install the package, hit `]` from the Julia command line to enter the package manager, then
 
 ```julia
-pkg> add https://github.com/kul-forbes/StructuredOptimization.jl
+pkg> add StructuredOptimization
 ```
 
 ## Usage

docs/src/index.md

@@ -21,7 +21,7 @@ StructuredOptimization.jl can handle large-scale convex and nonconvex problems w
 To install the package, hit `]` from the Julia command line to enter the package manager, then
 
 ```julia
-pkg> add https://github.com/kul-forbes/StructuredOptimization.jl
+pkg> add StructuredOptimization
 ```
 
 ## Citing