Update CHANGES.current and RELEASENOTES re PHP8

CHANGES.current

@@ -7,6 +7,9 @@ the issue number to the end of the URL: https://github.com/swig/swig/issues/
 Version 4.1.0 (in progress)
 ===========================
 
+2021-03-21: olly
+	    #1929, #1978 [PHP] Add support for PHP 8.
+
 2021-03-19: olly
 	    #1527 [PHP] Improve PHP object creation in directorin case.
 	    Reportedly the code we were using in this case gave segfaults in

RELEASENOTES

@@ -7,6 +7,9 @@ Release Notes
 Detailed release notes are available with the release and are also
 published on the SWIG web site at http://swig.org/release.html.
 
+SWIG-4.2.0 summary:
+- Add PHP 8 support.
+
 SWIG-4.0.2 summary:
 - A few fixes around doxygen comment handling.
 - Ruby 2.7 support added.