Changing the Data Type of Distbute Column in a Hash Rule Invariant Scenario

[Question]
In our production environment, due to the design problems of distribute column (too small in length), subsequent data can not be inserted properly.

```
app_db=# create table testdis1(c1 int, c2 varchar(30) primary key);
CREATE TABLE
app_db=# select create_distributed_table('testdis1','c2');
create_distributed_table
-----------------------------

(1 row)

app_db=# insert into testdis1 select 1,'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa';
ERROR: value too long for type character varying(30)
```

[try]
In this case, we want to change the data type of distribute column (varchar(30) -> varchar(50)),and the failed.
```
app_db=# alter table testdis1 alter c2 type varchar(50);
ERROR: cannot execute ALTER TABLE command involving partition column
app_db=#
```

[Ideas]
1. Redefine tables and import data into new tables. But since the total number of records is 49457,373,184, re-importing data can be time-consuming.

2. We believe that the hash rule algorithm of varchar(30) and varchar(50) should be the same. In this scenario, the data type of distribute column should be changed without re-publishing the data.

[hopes]
We hope that data type changes in Distbute Column in future versions of citus in scenarios where hash rules remain unchanged