v12.8.8

• fluent: an export no longer fails when a value is empty. Empty values are
  left out of the file, as intended.
• update fluent_conv dependency to 3.3.2 (fluent import and export):
  • a message with attributes but no value no longer fails the import, and
    exports as key = with its attributes instead of key = undefined
  • { login-input.placeholder } keeps its attribute (was { login-input })
  • { -brand(case: "accusative") } keeps its arguments (was { -brand })
  • minimumFractionDigits: 2 stays a number (was "2")
  • a function call with a literal argument, like { NUMBER(42) }, no longer
    fails the import