v1.2.3

Address InputFieldJsonWriter.writeCustom ignore encoded value (#1900)
Allow nested classes to have the same name as their parents in kotlin (#1893)
Fix json nesting issue with operation json writer (#1892)
Apollo coroutines are now on jcenter (#1862)
Fix Rx extension configure lambda do not use the returned instance (#1867)
Address callback is skipped for custom decorated okhttp calls (#1828)