Add setFill and setStroke to Shapes

This rounds out the shape style sto be more
consistent and make the `setFill` and `setStroke`
methods available.

src/ol/style/RegularShape.js

@@ -200,6 +200,15 @@ class RegularShape extends ImageStyle {
     return this.fill_;
   }
 
+  /**
+   * Set the fill style.
+   * @param {import("./Fill.js").default} fill Fill style.
+   * @api
+   */
+  setFill(fill) {
+    this.fill_ = fill;
+  }
+
   /**
    * @return {HTMLCanvasElement} Image element.
    */
@@ -309,6 +318,15 @@ class RegularShape extends ImageStyle {
     return this.stroke_;
   }
 
+  /**
+   * Set the stroke style.
+   * @param {import("./Stroke.js").default} stroke Stroke style.
+   * @api
+   */
+  setStroke(stroke) {
+    this.stroke_ = stroke;
+  }
+
   /**
    * @param {function(import("../events/Event.js").default): void} listener Listener function.
    */