Fix typo in README.md

README.md

@@ -171,7 +171,7 @@ make distclean
 
 PXF is an extension framework for GPDB to enable fast access to external hadoop datasets.
 Refer to [PXF extension](https://github.com/greenplum-db/gpdb/tree/master/gpAux/extensions/pxf) for more information.
-Currently, GPDPB is built with PXF by default (--enable-pxf is on).
+Currently, GPDB is built with PXF by default (--enable-pxf is on).
 In order to build GPDB without pxf, simply invoke `./configure` with additional option `--disable-pxf`.
 PXF requires curl, so `--enable-pxf` is not compatible with the `--without-libcurl` option.