bump install instructions to 3.2.2 tag

INSTALL.TXT

@@ -54,7 +54,7 @@ Alternatively :
   $ cd /srv
   $ git clone https://github.com/postfixadmin/postfixadmin.git
   $ cd postfixadmin
-  $ git checkout postfixadmin-3.2.1
+  $ git checkout postfixadmin-3.2.2
 
 2. Setup Web Server
 -------------------
@@ -192,4 +192,4 @@ IRC - a community of people may be able to help in #postfixadmin on irc.freenode
     See http://webchat.freenode.net/
 
 Legacy forum posts are on SourceForce at 
-    https://sourceforge.net/projects/postfixadmin
+    https://sourceforge.net/projects/postfixadmin