DATAES-977 - Fix versions in reference documentation for 4.1.

Author: sothawo

src/main/asciidoc/preface.adoc

@@ -34,7 +34,7 @@ The following table shows the Elasticsearch versions that are used by Spring Dat
 [cols="^,^,^,^",options="header"]
 |===
 | Spring Data Release Train |Spring Data Elasticsearch |Elasticsearch | Spring Boot
-| 2020.0.0footnote:cdv[Currently in development] |4.1.xfootnote:cdv[]|7.9.3 |2.3.xfootnote:cdv[]
+| 2020.0.0footnote:cdv[Currently in development] |4.1.xfootnote:cdv[]|7.9.3 |2.4.xfootnote:cdv[]
 | Neumann | 4.0.x | 7.6.2 |2.3.x
 | Moore | 3.2.x |6.8.12 | 2.2.x
 | Lovelace | 3.1.x | 6.2.2 |2.1.x