I am using VS Code 1.17.2 with the following extensions installed (Unfortuanetly i can\'t link them since i don\'t have enough reputation):
The extensions uses the settings that are set in your VS Code user settings file.
To change it, open your user settings file
Ctrl+Shift+P and type Open User Settings.
Open User Settings.
Search for prettier.singleQuote and change it to true like
prettier.singleQuote
"prettier.singleQuote": true