Cannot parse column rename sql without COLUMN keyword

[jackiezh]

Describe the bug
Cannot parse column rename sql without COLUMN keyword.

To Reproduce
Steps to reproduce the behavior:

1. Example SQL
   ALTER TABLE table_a RENAME col_a TO col_b;

2. Parsing this SQL using JSqlParser with this statements
   CCJSqlParserUtil.parse("ALTER TABLE table_a RENAME col_a TO col_b");

3. Exception
   net.sf.jsqlparser.parser.ParseException: Encountered unexpected token: "col_a" <S_IDENTIFIER>
   at line 1, column 28.

Was expecting:

"TO"

at net.sf.jsqlparser.parser.CCJSqlParser.generateParseException(CCJSqlParser.java:31468)
at net.sf.jsqlparser.parser.CCJSqlParser.jj_consume_token(CCJSqlParser.java:31301)
at net.sf.jsqlparser.parser.CCJSqlParser.AlterExpression(CCJSqlParser.java:17874)
at net.sf.jsqlparser.parser.CCJSqlParser.AlterTable(CCJSqlParser.java:17947)
at net.sf.jsqlparser.parser.CCJSqlParser.SingleStatement(CCJSqlParser.java:267)
at net.sf.jsqlparser.parser.CCJSqlParser.Statement(CCJSqlParser.java:153)
at net.sf.jsqlparser.parser.CCJSqlParserUtil.parseStatement(CCJSqlParserUtil.java:188)

System

• Database you are using: PostgreSQL
• Java Version: java-1.8
• JSqlParser version: 4.4

[manticore-projects]

The supported Syntax is shown here: http://217.160.215.75:8080/jsqlformatter/_static/JSqlParserCC.xhtml#AlterTable

Indeed the COLUMN keyword is mandatory.
In PostgreSQL COLUMN is supported, but optional:
ALTER TABLE [ IF EXISTS ] [ ONLY ] name [ * ] RENAME [ COLUMN ] column_name TO new_column_name