Update alpine Docker tag to v3.18.0

This MR contains the following updates:

Package	Type	Update	Change
alpine	ironbank-docker	minor	3.17.3 -> 3.18.0
alpine		minor	3.17.3 -> 3.18.0
alpine	final	minor	3.17.3 -> 3.18.0
alpine	stage	minor	3.17.3 -> 3.18.0

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