ALTER TABLE RENAME COLUMN command always can be used to rename the column
in the view, but it's reasonable to add that syntax to ALTER VIEW too.

Author: Fujii Masao
Reviewed-by: Ibrar Ahmed, Yu Kimura
Discussion: https://postgr.es/m/CAHGQGwHoQMD3b-MqTLcp1MgdhCpOKU7QNRwjFooT4_d+ti5v6g@mail.gmail.com