UPD: update to the NonlinearExpr syntax of JuMP v1.15 (#454) #659

Job	Run time
Julia 1.6 - ubuntu-latest - x64 - push	10m 52s
Julia 1.6 - macOS-latest - x64 - push	12m 39s
Julia 1.6 - windows-latest - x64 - push	30m 6s
Julia 1 - ubuntu-latest - x64 - push	8m 32s
Julia 1 - macOS-latest - x64 - push	12m 7s
Julia 1 - windows-latest - x64 - push	10m 4s
Julia nightly - ubuntu-latest - x64 - push	11m 58s
Julia nightly - macOS-latest - x64 - push	13m 49s
Julia nightly - windows-latest - x64 - push	12m 27s
	2h 2m 34s

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