You can use analytic function to update the column.
See the demo below:
Code:
SQL> select * from t1 ;

 OBJECT_ID OBJECT_NAME                    PROGRESSIVE
---------- ------------------------------ -----------
      2001 USER_VARRAYS                             1
      2002 USER_VARRAYS                             2
      2003 ALL_VARRAYS                              3
      2004 ALL_VARRAYS                              4
      2005 DBA_VARRAYS                              5
      2006 DBA_VARRAYS                              6
      2007 USER_OBJ_COLATTRS                        7
      2008 USER_OBJ_COLATTRS                        8
      2009 ALL_OBJ_COLATTRS                         9
      2010 ALL_OBJ_COLATTRS
      2011 DBA_OBJ_COLATTRS
      2012 DBA_OBJ_COLATTRS
      2013 USER_CONS_OBJ_COLUMNS
      2014 USER_CONS_OBJ_COLUMNS
      2015 ALL_CONS_OBJ_COLUMNS
      2016 ALL_CONS_OBJ_COLUMNS
      2017 DBA_CONS_OBJ_COLUMNS
      2018 DBA_CONS_OBJ_COLUMNS
      2019 ALL_SUMDELTA
      2020 ALL_SUMDELTA

20 rows selected.

SQL> get x2
  1  update t1 U
  2  set    u.progressive =
  3        ( select newval
  4           from
  5               (select object_id, object_name , maxval+rn newval
  6                 from ( select max(progressive) maxval
  7                         from t1
  8                         where progressive is not null
  9                      ) b,
 10                     ( select a.*, row_number() over (order by progressive) rn
 11                         from t1 a
 12                         where progressive is null
 13                     )
 14                ) O
 15            where O.object_id = u.object_id and
 16                  nvl(o.object_name,'x') = nvl(u.object_name ,'x')
 17         )
 18* where u.progressive is null
SQL> /

11 rows updated.

SQL> select * from t1 ;

 OBJECT_ID OBJECT_NAME                    PROGRESSIVE
---------- ------------------------------ -----------
      2001 USER_VARRAYS                             1
      2002 USER_VARRAYS                             2
      2003 ALL_VARRAYS                              3
      2004 ALL_VARRAYS                              4
      2005 DBA_VARRAYS                              5
      2006 DBA_VARRAYS                              6
      2007 USER_OBJ_COLATTRS                        7
      2008 USER_OBJ_COLATTRS                        8
      2009 ALL_OBJ_COLATTRS                         9
      2010 ALL_OBJ_COLATTRS                        10
      2011 DBA_OBJ_COLATTRS                        11
      2012 DBA_OBJ_COLATTRS                        12
      2013 USER_CONS_OBJ_COLUMNS                   13
      2014 USER_CONS_OBJ_COLUMNS                   14
      2015 ALL_CONS_OBJ_COLUMNS                    15
      2016 ALL_CONS_OBJ_COLUMNS                    16
      2017 DBA_CONS_OBJ_COLUMNS                    17
      2018 DBA_CONS_OBJ_COLUMNS                    18
      2019 ALL_SUMDELTA                            19
      2020 ALL_SUMDELTA                            20

20 rows selected.
Tamil