GithubCI: upgrade actions to latest version #2818

Job	Run time
linux-github--dotnet-and-newmono	9m 20s
linux-github--dotnet-and-mono	4m 34s
linux-vanilla--newmono-only	11m 16s
linux-vanilla--stockdotnet6-and-newmono	9m 30s
linux-vanilla--stockdotnet6-and-stockmono	8m 46s
linux-vanilla--stockdotnet6-only	6m 56s
linux-vanilla--stockmono-only	7m 3s
macOS--dotnet6-and-mono	21m 40s
macOS--dotnet6-only	4m 23s
macOS--mono-only	17m 54s
windows--dotnet6-and-legacyFramework	8m 59s
windows--dotnet6-only	8m 4s
windows--legacyFramework-only	16m 36s
conventions	1m 38s
snap_pkg	8m 17s
	2h 24m 56s

Provide feedback