Merge pull request #969 from Automattic/reproducible-builds #978

Job	Run time
Prepare build matrix	7s
Build Docker image (ref: 6.7.1, tag: 6.7)	1m 59s
Build Docker image (ref: 6.6.2, tag: 6.6)	2m 2s
Build Docker image (ref: 6.5.5, tag: 6.5)	1m 36s
Build Docker image (ref: 6.4.5, tag: 6.4)	1m 35s
Build Docker image (ref: 6.3.5, tag: 6.3)	1m 33s
Build Docker image (ref: 6.2.6, tag: 6.2)	1m 26s
Build Docker image (ref: 6.1.7, tag: 6.1)	1m 29s
Build Docker image (ref: 6.0.9, tag: 6.0)	1m 30s
Build Docker image (ref: HEAD, tag: trunk)	1m 29s
	14m 46s

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