AdGuard Go Team YAML guidelines

TODO(a.garipov): Define naming conventions for schema names in our OpenAPI YAML file. And just generally OpenAPI conventions.
TODO(a.garipov): Find a YAML formatter or write our own.
§ All strings, including keys, must be quoted. Reason: the “NO-rway Law”.
§ Indent with four (4) spaces.
§ Multiline arrays should be formatted with two spaces, one hyphen, and one space:
```
'values':
  - 'value-1'
  - 'value-2'
  - 'value-3'
```
although four spaces before a hyphen is acceptable, when a program formats a document that way:
```
'values':
    - 'value-1'
    - 'value-2'
    - 'value-3'
```
§ Prefer single quotes for strings to prevent accidental escaping, unless escaping is required or there are single quotes inside the string (e.g. for GitHub Actions).
§ Use > for multiline strings, unless you need to keep the line breaks. Use | for multiline strings when you do.

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