Update version to 5.2.0.0, Hilda mandatory release.

Author: jamescowens

configure.ac

@@ -1,11 +1,11 @@
 dnl require autoconf 2.60 (AS_ECHO/AS_ECHO_N)
 AC_PREREQ([2.60])
 define(_CLIENT_VERSION_MAJOR, 5)
-define(_CLIENT_VERSION_MINOR, 1)
+define(_CLIENT_VERSION_MINOR, 2)
 define(_CLIENT_VERSION_REVISION, 0)
-define(_CLIENT_VERSION_BUILD, 12)
-define(_CLIENT_VERSION_IS_RELEASE, false)
-define(_COPYRIGHT_YEAR, 2020)
+define(_CLIENT_VERSION_BUILD, 0)
+define(_CLIENT_VERSION_IS_RELEASE, true)
+define(_COPYRIGHT_YEAR, 2021)
 define(_COPYRIGHT_HOLDERS,[The %s developers])
 define(_COPYRIGHT_HOLDERS_SUBSTITUTION,[[Gridcoin]])
 AC_INIT([Gridcoin],[_CLIENT_VERSION_MAJOR._CLIENT_VERSION_MINOR._CLIENT_VERSION_REVISION],[https://github.com/gridcoin/Gridcoin-Research/issues],[gridcoin],[https://gridcoin.us/])