Add instructions for using Docker Compose #3

Job	Run time
3.7 CH=23.8.4.69	59s
3.7 CH=22.5.1.2079	58s
3.7 CH=19.3.5	1m 1s
3.7 CH=18.14.9	53s
3.8 CH=23.8.4.69	45s
3.8 CH=22.5.1.2079	43s
3.8 CH=19.3.5	42s
3.8 CH=18.14.9	27s
3.9 CH=23.8.4.69	35s
3.9 CH=22.5.1.2079	34s
3.9 CH=19.3.5	32s
3.9 CH=18.14.9	37s
3.10 CH=23.8.4.69	43s
3.10 CH=22.5.1.2079	45s
3.10 CH=19.3.5	28s
3.10 CH=18.14.9	34s
3.11 CH=23.8.4.69	38s
3.11 CH=22.5.1.2079	32s
3.11 CH=19.3.5	40s
3.11 CH=18.14.9	26s
3.12 CH=23.8.4.69	1m 12s
3.12 CH=22.5.1.2079	57s
3.12 CH=19.3.5	56s
3.12 CH=18.14.9	1m 1s
Indicate completion to coveralls.io	6s
	17m 44s

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