Update eslint settings for jsx-quotes

1) jsx-quotes is now part of ESLint itself:
jsx-eslint/eslint-plugin-react#217
2) setting jsx-quotes to "prefer-single", i.e. single quote unless
the string contains a single quote.

Author: ezmiller

beavy/jsbeavy/.eslintrc

@@ -23,7 +23,7 @@
 	},
 	"rules": {
 		"react/jsx-boolean-value": 2,
-		"react/jsx-quotes": 2,
+		"jsx-quotes": [2, "prefer-single"],
 		"react/jsx-no-undef": 2,
 		"react/jsx-sort-props": 0,
 		"react/jsx-sort-prop-types": 0,