Sign self generated DTLS certificate with SHA256 #4786

Job	Run time
ci (ubuntu-20.04, gcc, g++, true, 22, Release)	9m 14s
ci (ubuntu-20.04, gcc, g++, true, 22, Debug)	9m 14s
ci (ubuntu-20.04, clang, clang++, true, 22, Release)	9m 13s
ci (ubuntu-20.04, clang, clang++, true, 22, Debug)	9m 14s
ci (ubuntu-22.04, gcc, g++, 22, Release)	9m 12s
ci (ubuntu-22.04, gcc, g++, 22, Debug)	9m 13s
ci (ubuntu-22.04, clang, clang++, 22, Release)	9m 2s
ci (ubuntu-22.04, clang, clang++, 22, Debug)	9m 13s
ci (ubuntu-24.04, gcc, g++, true, 22, Release)	9m 11s
ci (ubuntu-24.04, gcc, g++, true, 22, Debug)	9m 11s
ci (ubuntu-24.04, clang, clang++, true, 22, Release)	9m 12s
ci (ubuntu-24.04, clang, clang++, true, 22, Debug)	9m 13s
ci (macos-12, gcc, g++, true, 22, Release)	9m 15s
ci (macos-12, gcc, g++, true, 22, Debug)	9m 13s
ci (macos-14, clang, clang++, true, 22, Release)	4m 45s
ci (macos-14, clang, clang++, true, 22, Debug)	5m 48s
ci (windows-2022, cl, cl, 22, Release)	7m 26s
ci (windows-2022, cl, cl, 22, Debug)	6m 33s
	2h 33m 22s

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