doc: update version to 5.0.0 in prep for GA release

Author: hzhou

CHANGES

@@ -1,5 +1,5 @@
 ===============================================================================
-                               Changes in 5.0
+                               Changes in 5.0.0
 ===============================================================================
 # MPI_VERSION/MPI_SUBVERSION updated to 5 and 0. MPICH now supports the MPI 5.0
   standard.

maint/version.m4

@@ -14,7 +14,7 @@
 # changing this by playing with diversions, but then we would probably be
 # playing with autotools-fire.
 
-m4_define([MPICH_VERSION_m4],[5.0.0rc3])dnl
+m4_define([MPICH_VERSION_m4],[5.0.0])dnl
 m4_define([MPICH_RELEASE_DATE_m4],[unreleased development copy])dnl
 
 # For libtool ABI versioning rules see:
@@ -37,7 +37,7 @@ m4_define([MPICH_RELEASE_DATE_m4],[unreleased development copy])dnl
 
 # Use [0:0:0] for unstable (e.g. alpha and beta) releases.
 
-# last version 4.3.0 - 17:0:5
+# last version 5.0.0 - 18:0:6
 m4_define([libmpi_so_version_m4],[0:0:0])dnl
 
 # libmpi_abi.so version