fix(readme): use correct variable name

Co-authored-by: Dylan Fiedler <dtfiedler@users.noreply.github.com>

README.md

@@ -557,7 +557,7 @@ Returns all records on the configured ANT contract, including the required `@` r
 ```typescript
 const contractTxId = 'bh9l1cy0aksiL_x9M359faGzM_yjralacHIUo8_nQXM';
 const ant = new ANT({ contractTxId });
-const records = await ANT.getRecords();
+const records = await ant.getRecords();
 
 // output
 // {