fix token flush CLI description

[sawadashota]

Related issue

none

Proposed changes

"1d" is unavailable unit so that I fixed token flush CLI description.
Only we can use these units: "ns", "us" (or "µs"), "ms", "s", "m", "h".
https://godoc.org/time#ParseDuration

Checklist

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  vulnerability, I confirm that I got green light (please contact hi@ory.sh) from the maintainers to push the changes.
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• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation within the code base (if appropriate)
• I have documented my changes in the developer guide (if appropriate)

Further comments

[aeneasr]

Thank you!