Build failure insert_values_clause

[GrumpyLittleTed]

The current build is failing with a webpack error due to missing types in postgresql.pegjs:

The fix is as follows (sorry I cannot do a PR at the moment)

│ 4125 insert_value_clause │
│ 4126 - = value_clause │
│ 4126 + = value_clause { │
│ 4127 + /* => { type: │
│ 'values', values: │
│ value_list } / │
│ 4128 + return { type: │
│ 'values', values: value } │
│ 4129 + } │
│ 4130 / u:union_stmt { │
│ 4131 + / => │
│ union_stmt_node */ │
│ 4132 return u.ast │
│ 4133 }