Fixed size type (#40318)

Amended type of `size` field from `string` to `number`

types/ftp/index.d.ts

@@ -1,4 +1,4 @@
-// Type definitions for ftp 0.3.8
+// Type definitions for ftp 0.3.9
 // Project: https://github.com/mscdex/node-ftp
 // Definitions by: Rogier Schouten <https://github.com/rogierschouten>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
@@ -70,7 +70,7 @@ declare namespace Client {
         /**
          * The size of the entry in bytes
          */
-        size: string;
+        size: number;
         /**
          * The last modified date of the entry
          */