fix: Cloud SQL does not support multiple deny_maintenance_period block. Update variable description

[olaoluwasalami]

Resolves #546

[google-cla]

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[olaoluwasalami]

@isaurabhuttam @imrannayer

signing the CLA, I get this error A server error occurred, please try your request again. Do you know what might be wrong?

[imrannayer]

@olaoluwasalami can u try again by pressing button on this page?

https://github.com/terraform-google-modules/terraform-google-sql-db/pull/564/checks?check_run_id=19988151134

[olaoluwasalami]

Do you mean the refresh button? @imrannayer . Doesn't work, if yes

[g-awmalik]

/gcbrun

[g-awmalik]

@olaoluwasalami - can you try signing the CLA again please?

[olaoluwasalami]

@g-awmalik CLA signed

[imrannayer]

/gcbrun

[imrannayer]

@olaoluwasalami can u plz fix lint issues? Follow the doc

[g-awmalik]

/gcbrun