When you need to unify your YAML file to use double quote for strings you can use the following regular expressions and the replacement to use on your favorite editor.
The first lines are the regex to find and the last lines are the replace expressions.
Convert single quoted values to double in YAML
key: 'value' will be converted to
Escape doube quotes inside doube quoted strings in YAML
Needs to be run multiple times until no match is found.
key: "field "name" is empty" will be converted to
key: "field \"name\" is empty"