The following liquibase changeset does not work as expected

```xml
        <createTable tableName="test">
            <column name="id" type="SERIAL">
                <constraints nullable="false" primaryKey="true"/>
            </column>
        </createTable>
```

This changeset results in sql

```sql
CREATE TABLE test (id INTEGER NOT NULL, CONSTRAINT TEST_PKEY PRIMARY KEY (id));
```

In liquibase 3.6.3 and earlier the type `SERIAL` was used for the column which means that a sequence is automatically included.

This issue seems to be caused by #874
It appears that SERIAL columns are replaced by INT, however liquibase does reconize that this column type is an auto increment column.

It would be acceptible if the generated sql would be

```sql
CREATE TABLE test (id INTEGER GENERATED BY DEFAULT AS IDENTITY NOT NULL, CONSTRAINT TEST_PKEY PRIMARY KEY (id));
```


}
        if (database instanceof OracleDatabase) {
            return new DatabaseDataType("NUMBER", 38,0);
        }
        if (database instanceof SybaseDatabase) {
            return new DatabaseDataType("BIGINT");
        }
        if (database instanceof MSSQLDatabase) {
            return new DatabaseDataType(database.escapeDataTypeName("bigint"));
        }
        if (database instanceof MySQLDatabase) {
            DatabaseDataType type = new DatabaseDataType("BIGINT");
            type.addAdditionalInformation(getAdditionalInformation());
            return type;
        }
        if ((database instanceof AbstractDb2Database) || (database instanceof DerbyDatabase) || (database instanceof
            HsqlDatabase) || (database instanceof FirebirdDatabase)) {
            return new DatabaseDataType("BIGINT");
        }
        if (database instanceof PostgresDatabase) {
            if (isAutoIncrement()) {
                int majorVersion = 9;
                try {
                    majorVersion = database.getDatabaseMajorVersion();
                } catch (DatabaseException e) {
                    
                }
                if (majorVersion < 10) {
                    return new DatabaseDataType("BIGSERIAL");
                }