Use elm-pep instead of PEP as pointer events polyfill

package.json

@@ -36,7 +36,7 @@
     "url": "https://github.com/openlayers/openlayers/issues"
   },
   "dependencies": {
-    "@openlayers/pepjs": "^0.5.3",
+    "elm-pep": "^1.0.2",
     "pbf": "3.2.1",
     "pixelworks": "1.1.0",
     "rbush": "^3.0.1"

src/ol/MapBrowserEventHandler.js

@@ -2,7 +2,7 @@
  * @module ol/MapBrowserEventHandler
  */
 
-import '@openlayers/pepjs';
+import 'elm-pep';
 import {DEVICE_PIXEL_RATIO} from './has.js';
 import MapBrowserEventType from './MapBrowserEventType.js';
 import MapBrowserPointerEvent from './MapBrowserPointerEvent.js';

src/ol/control/MousePosition.js

@@ -1,12 +1,13 @@
 /**
  * @module ol/control/MousePosition
  */
+
+import 'elm-pep';
 import {listen} from '../events.js';
 import EventType from '../pointer/EventType.js';
 import {getChangeEventType} from '../Object.js';
 import Control from './Control.js';
 import {getTransformFromProjections, identityTransform, get as getProjection, getUserProjection} from '../proj.js';
-import '@openlayers/pepjs';
 
 
 /**

src/ol/control/ZoomSlider.js

@@ -1,6 +1,8 @@
 /**
  * @module ol/control/ZoomSlider
  */
+
+import 'elm-pep';
 import Control from './Control.js';
 import {CLASS_CONTROL, CLASS_UNSELECTABLE} from '../css.js';
 import {easeOut} from '../easing.js';
@@ -9,7 +11,6 @@ import {stopPropagation} from '../events/Event.js';
 import EventType from '../events/EventType.js';
 import {clamp} from '../math.js';
 import PointerEventType from '../pointer/EventType.js';
-import '@openlayers/pepjs';
 
 
 /**