Update JDK version in build instruction

For javacard compatible with jcdk v3.0.4 (or lower), use JDK 8 or 11.
Using jdk 17 gives the following error:

The applet build from master shows the following with JDK17:

---
Buildfile: /home/.../SatochipApplet/build.xml

build:
      [cap] INFO: using JavaCard 3.0.4 SDK in /home/.../SatochipApplet/sdks/jc304_kit with JDK 17
      [cap] INFO: Setting package name to org.satochip.applet
      [cap] Building CAP with 1 applet from package org.satochip.applet (AID: 5361746F43686970)
      [cap] org.satochip.applet.CardEdge 5361746F4368697000
  [compile] Compiling files from /home/.../SatochipApplet/src/org/satochip/applet

BUILD FAILED
/home/.../SatochipApplet/build.xml:15: Can't use JDK 17 with JavaCard kit 3.0.4 (use JDK 11)

Author: Toporin

README.md

@@ -82,7 +82,7 @@ https://github.com/martinpaljak/ant-javacard/releases/latest/download/ant-javaca
 sudo apt install ant
 ```
 
-* Use/install [recommended](https://github.com/martinpaljak/ant-javacard/wiki/JavaCard-SDK-and-JDK-version-compatibility) java JDK 8 or 17
+* Use/install [recommended](https://github.com/martinpaljak/ant-javacard/wiki/JavaCard-SDK-and-JDK-version-compatibility) java JDK 8 or 11
 ```
 sudo update-alternatives --config java
 ```