chore: reset v18 package versions to 18.0.0

Nothing has shipped to npm yet for PG 18 (no 18.x on registry for
@pgsql/types or @pgsql/enums), and the previous 18.0.1/18.0.2 bumps
were paired with stale src/ generated from PG 17. Resetting so the
first real PG 18 publish lands as a clean 18.0.0.

  - types/18:    18.0.2 -> 18.0.0
  - enums/18:    18.0.1 -> 18.0.0
  - versions/18: 18.0.1 -> 18.0.0

Author: pyramation

enums/18/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@libpg-query/enums18",
-  "version": "18.0.1",
+  "version": "18.0.0",
   "author": "Constructive <developers@constructive.io>",
   "description": "PostgreSQL AST enums from the real Postgres parser",
   "main": "index.js",

types/18/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@libpg-query/types18",
-  "version": "18.0.2",
+  "version": "18.0.0",
   "author": "Constructive <developers@constructive.io>",
   "description": "PostgreSQL AST types from the real Postgres parser",
   "main": "index.js",

versions/18/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@libpg-query/v18",
-  "version": "18.0.1",
+  "version": "18.0.0",
   "description": "The real PostgreSQL query parser",
   "homepage": "https://github.com/constructive-io/libpg-query-node",
   "main": "./wasm/index.cjs",