Remove schema/table name from the update columns key

Using the schema name for a column generates an error within Cockroach:

SQLSTATE[0A000]: Feature not supported: 7 ERROR:  at or near \"table\": syntax error: unimplemented
HINT:  You have attempted to use a feature that is not yet implemented. See: https://go.crdb.dev/issue-v/27792/v21.1

The update column name is automatically generated by eloquent for columns such as timestamps as '"schema"."table"."updated_at", which is invalid for Postgres and Cockroach.

Similar to issues seen in laravel/framework#13707

src/Cockroach/Grammar/Query/CockroachGrammar.php

@@ -131,7 +131,7 @@ protected function compileUpdateColumns(Builder $query, array $values)
         // columns and convert it to a parameter value. Then we will concatenate a
         // list of the columns that can be added into this update query clauses.
         return collect($values)->map(function ($value, $key) {
-            return $this->wrap($key).' = '.$this->parameter($value);
+            return $this->wrap(end(explode('.', $key))).' = '.$this->parameter($value);
         })->implode(', ');
     }