Merge pull request #593 from AlexWayfer/add_editorconfig_file #676

Job	Run time
Build	4s
Test (windows, head, 16.0-1-windows-x64, 16)	2m 28s
Test (windows, 2.5, 9.4.26-1-windows-x64, 9.4)	7m 19s
Test (windows, mswin, 16.0-1-windows-x64, 16)	1m 46s
Test (ubuntu, head, 16)	1m 2s
Test (ubuntu, 3.2, 12)	1m 9s
Test (ubuntu, 20.04, 2.5, 9.3)	1m 49s
Test (ubuntu, truffleruby, 13)	1m 47s
Test (ubuntu, truffleruby-head, 16)	1m 45s
Test (macos, head, 16.0-1-osx, 16)	2m 31s
	21m 40s

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