Add supporting themes required for Lotusdocs

themes/hugo-mod-jslibs-dist/popperjs/package/lib/dom-utils/isScrollParent.js.flow

@@ -0,0 +1,8 @@
+// @flow
+import getComputedStyle from './getComputedStyle';
+
+export default function isScrollParent(element: HTMLElement): boolean {
+  // Firefox wants us to check `-x` and `-y` variations as well
+  const { overflow, overflowX, overflowY } = getComputedStyle(element);
+  return /auto|scroll|overlay|hidden/.test(overflow + overflowY + overflowX);
+}