boards: adi: apard32690: Updated References index.rst

Updated the reference to the ADI Developer Portal Solution Center with
URL. The Solution Center provides more resources than the product
information. Users can still find the product information from the new
portal link.

Signed-off-by: Janel Kratky <[email protected]>

Author: jcandkk

boards/adi/apard32690/doc/index.rst

@@ -209,7 +209,7 @@ instead of ``west flash``.
 References
 **********
 
-- `AD-APARD32690-SL web page`_
+- `AD-APARD32690-SL solution center`_
 
-.. _AD-APARD32690-SL web page:
-   https://www.analog.com/en/resources/evaluation-hardware-and-software/evaluation-boards-kits/ad-apard32690-sl.html
+.. _AD-APARD32690-SL solution center:
+   https://developer.analog.com/solutions/max32690