[TASK] Adjust hint that ELTS ran out for TYPO3 v8.7 (#370)

The ELTS has reached end-of-life on March 31st, 2024.

Releases: 8.7

Documentation/Includes.rst.txt

@@ -38,5 +38,5 @@
    maintained by the community anymore. Looking for a stable version?
    Use the version switch on the top left.
 
-   You can order Extended Long Term Support (ELTS) here:
-   `TYPO3 ELTS <https://typo3.com/services/extended-support-elts>`__.
+   There is no further ELTS support. It is recommended that you upgrade your
+   project and use a supported version of TYPO3.