JuMP v0.23.0

Diff since v0.22.3

Closed issues:

• Refactor print to using printing implemented for MOI backend (#2814)
• Add function to set all start values for constraints and variables based on current solution (#2836)
• [docs] Mention CasADi as an alternative to JuMP (#2871)
• Expose NLPBlockDualStart (#2875)
• [docs] update MILP examples to HiGHS (#2878)
• Rename nl_ functions to nonlinear_ (#2882)
• Symmetric vs SkewSymmetric Variables (#2884)

Merged pull requests:

• Preliminary support for complex numbers (#2391) (@blegat)
• [docs] improve section on constraint start values (#2861) (@odow)
• [docs] fix typo in design patterns tutorial (#2870) (@odow)
• [docs] add CasADi to Should I use JuMP? (#2872) (@odow)
• Allow NaNMath 1.0 (#2873) (@mlubin)
• [breaking] remove PrintMode instead of explicit MIME types (#2874) (@odow)
• WIP: prep for v1.0 (#2876) (@odow)
• Remove deprecated functionality (#2877) (@odow)
• Add nl_dual_start_value (#2879) (@odow)
• Fix bug in solution summary (#2880) (@odow)
• [docs] switch from GLPK to HiGHS (#2881) (@odow)
• [breaking] rename nl_ functions to nonlinear_ (#2885) (@odow)
• [docs] clarify return type of SkewSymmetricMatrixSpace (#2888) (@odow)
• [breaking] rename SymMatrixSpace to SymmetricMatrixSpace (#2889) (@odow)
• Fix addition/substraction between variable and complex number (#2890) (@blegat)
• Prep for v0.23 (#2891) (@odow)