Update version number to 2.2.2

Author: microfarad-de

pi-ups.ino

@@ -23,8 +23,8 @@
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  *
- * Version: 2.2.1
- * Date:    March 2020
+ * Version: 2.2.2
+ * Date:    June 2020
  */
 #define VERSION_MAJOR 2  // major version
 #define VERSION_MINOR 2  // minor version