GithubCI: switch to MacOS 13 #4147

Job	Run time
windows--dotnet6-and-legacyFramework	6m 1s
macOS--mono-only	16m 44s
linux20-vanilla--stockmono-only	5m 43s
linux20-github--dotnet-and-mono	4m 2s
linux20-github--dotnet-and-newmono	4m 26s
linux22-github--dotnet-and-mono	4m 32s
linux22-github--dotnet-and-newmono	4m 1s
linux22-vanilla--newmono-only	6m 22s
linux22-vanilla--stockdotnet6-and-newmono	5m 50s
linux22-vanilla--stockdotnet6-and-stockmono	5m 13s
linux22-vanilla--stockdotnet6-only	5m 5s
linux22-vanilla--stockmono-only	5m 25s
macOS--dotnet6-and-mono	9m 42s
macOS--dotnet6-only	6m 35s
windows--dotnet6-only	6m 55s
windows--legacyFramework-only	14m 2s
linux20-vanilla--newmono-only	6m 42s
conventions	1m 21s
snap_pkg	3m 48s
	2h 2m 29s

Provide feedback