Update how-to-update-your-streamr-node.md

[Karjack182]

added documentation for updating with docker compose

Summary

Please provide a summary of the changes and a motivation if applicable.

Changes

Provide a bullet list of individual changes. Leave this section out if change
set is small and obvious from summary.

Limitations and future improvements

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solution and/or any ideas for future improvement. Leave section ouf if
not applicable.

Checklist before requesting a review

• Is this a breaking change? If it is, be clear in summary.
• Read through code myself one more time.
• Make sure any and all TODO comments left behind are meant to be left in.
• Has reasonable passing test coverage?
• Updated changelog if applicable.
• Updated documentation if applicable.

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