Add tabs with Arty35 and Arty100 to README

Signed-off-by: Tomasz Michalak <tmichalak@antmicro.com>

xc7/picosoc_demo/README.rst

@@ -4,6 +4,18 @@ PicoSoC demo
 This example features a picorv32 soft CPU and a SoC based on it. To build the
 picosoc example, run the following commands:
 
+.. code-block:: bash
+   :name: example-picosoc-a35t-group
+
+   TARGET="arty_35" make -C picosoc_demo
+
+
+.. code-block:: bash
+   :name: example-picosoc-a100t-group
+
+   TARGET="arty_100" make -C picosoc_demo
+
+
 .. code-block:: bash
    :name: example-picosoc-basys3-group