Add 4.0.0 release date

ANNOUNCE

@@ -1,4 +1,4 @@
-*** ANNOUNCE: SWIG 4.0.0 (in progress) ***
+*** ANNOUNCE: SWIG 4.0.0 (27 Apr 2019) ***
 
 http://www.swig.org
 

CHANGES.current

@@ -4,7 +4,7 @@ See the RELEASENOTES file for a summary of changes in each release.
 Issue # numbers mentioned below can be found on Github. For more details, add
 the issue number to the end of the URL: https://github.com/swig/swig/issues/
 
-Version 4.0.0 (in progress)
+Version 4.0.0 (27 Apr 2019)
 ===========================
 
 2019-04-24: vadz

Doc/Manual/Sections.html

@@ -8,7 +8,7 @@
 <H1><a name="Sections">SWIG-4.0 Documentation</a></H1>
 
 <p>
-Last update : SWIG-4.0.0 (in progress)
+Last update : SWIG-4.0.0 (27 Apr 2019)
 </p>
 
 <H2><a name="Sections_Sections">Sections</a></H2>

README

@@ -1,6 +1,6 @@
 SWIG (Simplified Wrapper and Interface Generator)
 
-Version: 4.0.0 (in progress)
+Version: 4.0.0 (27 Apr 2019)
 
 Tagline: SWIG is a compiler that integrates C and C++ with languages
          including Perl, Python, Tcl, Ruby, PHP, Java, C#, D, Go, Lua,