Add final declaration

Author: BielinskiLukasz

src/main/java/com/assertthat/selenium_shutterbug/utils/image/ImageProcessor.java

@@ -25,7 +25,7 @@
 public class ImageProcessor {
 
     private static final int ARCH_SIZE = 10;
-    private static float[] matrix = new float[49];
+    private static final float[] matrix = new float[49];
     private static double pixelError = Double.MAX_VALUE;
 
     static {

src/main/java/com/assertthat/selenium_shutterbug/utils/web/Coordinates.java

@@ -14,10 +14,10 @@
  */
 public class Coordinates {
 
-    private int width;
-    private int height;
-    private int x;
-    private int y;
+    private final int width;
+    private final int height;
+    private final int x;
+    private final int y;
 
     public Coordinates(WebElement element, Double devicePixelRatio) {
         Point point = element.getLocation();