nuget: bump the nunit group with 2 updates #70

Job	Run time
format	3m 14s
pr_build / macOS Universal (Debug)	6m 10s
pr_build / win-x64 (Debug)	3m 4s
pr_build / macOS Universal (Release)	6m 11s
pr_build / linux-x64 (Debug)	1m 29s
pr_build / linux-arm64 (Debug)	1m 24s
pr_build / osx-x64 (Debug)	2m 22s
pr_build / win-x64 (Release)	3m 26s
pr_build / linux-x64 (Release)	1m 13s
pr_build / linux-arm64 (Release)	1m 9s
pr_build / osx-x64 (Release)	2m 1s
	31m 43s

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