Suppress sass deprecation warning

[wonda-tea-coffee]

Motivation / Background

Addressed sass deprecation warning.

Detail

The following deprecation warning was addressed.

Deprecation Warning: Sass's behavior for declarations that appear after nested
rules will be changing to match the behavior specified by CSS in an upcoming
version. To keep the existing behavior, move the declaration above the nested
rule. To opt into the new behavior, wrap the declaration in `& {}`.

More info: https://sass-lang.com/d/mixed-decls

    ╷
5   │ ┌     label {
6   │ │       display: none;
7   │ │     }
    │ └─── nested rule
... │
5   │ ┌     label {
6   │ │       display: none;
7   │ │     }
    │ └─── nested rule
... │
9   │       margin-bottom: 5px;
    │       ^^^^^^^^^^^^^^^^^^ declaration
    ╵
    vendor/bundle/gems/activeadmin_addons-1.10.1/app/assets/stylesheets/activeadmin_addons/inputs/date-ti
me-picker-filter.scss 9:5  @import
(snip)

Additional information

This warning is due to the following change in dart-sass.
sass/dart-sass#2267

Checklist

Before submitting the PR make sure the following are checked:

• This Pull Request is related to one change. Changes that are unrelated should be opened in separate PRs.
• Commit message has a concise description of what changed and why.
• Tests are added or updated if you fix a bug or add a feature.
• Documentation has been added or updated if you add a feature or modify an existing one.
• CHANGELOG files are updated for the changed libraries if there is a behavior change or additional feature (under the "Unreleased" heading if this is not a version change).
• My changes don't introduce any linter rule violations.

[wonda-tea-coffee]

I am guessing because I can't see the CircleCI results screen, but since it was this job that failed, at least this change is irrelevant since it is scss only.
https://github.com/platanus/activeadmin_addons/blob/master/.circleci/config.yml#L66-L83