Allow setting text alignment, and default to centered text

src/index.js

@@ -20,7 +20,8 @@ module.exports = function createPlaceholderRectangle(options = {}) {
 			text: createText({
 				fontSize: 14,
 				originX: "center",
-				originY: "center"
+				originY: "center",
+				alignment: "center"
 			})
 		},
 		drawOrder: ["rectangle", "text"],
@@ -31,6 +32,7 @@ module.exports = function createPlaceholderRectangle(options = {}) {
 			textFillColor: "text.fillColor",
 			textStrokeColor: "text.strokeColor",
 			textStrokeWidth: "text.strokeWidth",
+			alignment: "text",
 			fontSize: "text",
 			fontFamily: "text",
 			fontWeight: "text",