feat: add solutions to lc problem: No.2723 (#2055)

Author: iam-abhishek-yadav

solution/2700-2799/2723.Add Two Promises/README.md

@@ -62,4 +62,12 @@ async function addTwoPromises(
  */
 ```
 
+### **JavaScript**
+
+```js
+var addTwoPromises = async function (promise1, promise2) {
+    return (await promise1) + (await promise2);
+};
+```
+
 <!-- tabs:end -->

solution/2700-2799/2723.Add Two Promises/README_EN.md

@@ -54,4 +54,12 @@ async function addTwoPromises(
  */
 ```
 
+### **JavaScript**
+
+```js
+var addTwoPromises = async function (promise1, promise2) {
+    return (await promise1) + (await promise2);
+};
+```
+
 <!-- tabs:end -->

solution/2700-2799/2723.Add Two Promises/solution.js

@@ -0,0 +1,3 @@
+var addTwoPromises = async function (promise1, promise2) {
+    return (await promise1) + (await promise2);
+};