snakeyaml may have to serialize a String value as a !!binary tagged base64 encoded value

An example would be a (Java) String embedding a non-serializable character, for example:

 String qux = String.valueOf((char)27); // see hippo-repository/engine/src/test/java/org/onehippo/repository/xml/EnhancedImportTest.java

In JCR esv format such string values will also be base64 encoded, but the Yaml spec may have different rules what can/cannot be serialize without encoding.

At any rate, snakeyaml will base64 encode the example string above, tagging the value with !!binary so that it can be read in again:

qux: !!binary |-
       Gw==

However, this loses the original/expected scalar string type, making it binary after reading back in.
Instead what we need to retain the type info, it should be serialized something like:

qux:
  type: string
  value: !!binary |-
       Gw==