Update references to latest AtoM version number from 2.8.0 to 2.8.2

Note that there is still an outstanding reference to 2.8.0 that comes from line 232. However, the reference is indirect and uses the placeholder |release|.

admin-manual/installation/ubuntu.rst

@@ -235,9 +235,9 @@ Option 1: Download the tarball
 
 .. code-block:: bash
 
-   wget https://storage.accesstomemory.org/releases/atom-2.8.0.tar.gz
+   wget https://storage.accesstomemory.org/releases/atom-2.8.2.tar.gz
    sudo mkdir /usr/share/nginx/atom
-   sudo tar xzf atom-2.8.0.tar.gz -C /usr/share/nginx/atom --strip 1
+   sudo tar xzf atom-2.8.2.tar.gz -C /usr/share/nginx/atom --strip 1
 
 Please note that the tarball may not be available yet if this version is still
 in development. In this case, you can try the alternative installation method