update packages and add valign

scripts/reveal.js/js/controllers/keyboard.js

@@ -1,4 +1,4 @@
-import { enterFullscreen } from '../utils/util.js'
+import { enterFullscreen } from '../utils/util'
 
 /**
  * Handles all reveal.js keyboard interactions.
@@ -398,6 +398,12 @@ export default class Keyboard {
 
 			event.preventDefault && event.preventDefault();
 		}
+		
+		// Enter to exit overview mode
+		else if (keyCode === 13 && this.Reveal.overview.isActive()) {
+			this.Reveal.overview.deactivate();
+			event.preventDefault && event.preventDefault();
+		}
 
 		// If auto-sliding is enabled we need to cue up
 		// another timeout