[docker] Update ECS to 1.12

[marc-gr]

Automated PR.

Updates ECS to v1.12 and does the required changes to the package.

[elasticmachine]

Pinging @elastic/integrations (Team:Integrations)

[elasticmachine]

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Build stats

• Start Time: 2021-09-28T09:07:09.837+0000

• Duration: 17 min 8 sec

• Commit: 98773a3

Test stats 🧪

Test	Results
Failed	0
Passed	36
Skipped	0
Total	36

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