merge: Add test case to Interpolation Search Algorithm (TheAlgorithms#1045)

* Add test case to Interpolation Search Algorithm

* Updated Documentation in README.md

Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>

Author: Ankush263

Search/test/InterpolationSearch.test.js

@@ -0,0 +1,15 @@
+import { interpolationSearch } from '../InterpolationSearch'
+
+test('interpolationSearch([2, 6, 8, 14, 122, 169], 144) => -1', () => {
+  const array = [2, 6, 8, 14, 122, 169]
+  const key = 144
+  const res = interpolationSearch(array, key)
+  expect(res).toEqual(-1)
+})
+
+test('interpolationSearch([2, 6, 8, 14, 122, 169], 122) => 4', () => {
+  const array = [2, 6, 8, 14, 122, 169]
+  const key = 122
+  const res = interpolationSearch(array, key)
+  expect(res).toEqual(4)
+})