Update configuration-reference.adoc

[HennaAbbas]

we no longer support a docker version, instead you must use "default" , "current" or "edge". To use the current deprecated version, you can specify 20.10.24

Description

we no longer support a docker version, instead you must use "default" , "current" or "edge". To use the current deprecated version, you can specify 20.10.24. Therefore, I updated the example config to use "default" as the version

Reasons

A link to a GitHub and/or JIRA issue (if applicable). New supportedformat for default.

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[maciej-chime]

@HennaAbbas from the previous PR, do we also need to fix the version here?