Class fields not supported by linter

[adalinesimonian]

Describe the problem and steps to reproduce it:

(Please include as many details as possible.)

1. Create an extension with a javascript file that uses class fields (supported by Firefox 69 and above).
2. Run the linter

What happened?

What did you expect to happen?

Validation passes without errors.

Anything else we should know?

(Please include screenshots and any relevant files.)

Error still happens even though the extension in question has the following in manifest.json:

  "browser_specific_settings": {
    "gecko": {
      "strict_min_version": "70.0"
    }
  },

[jetwitaussi]

Same problem :(

[willdurand]

duplicate of #3062