fix(deps): update dependency pg to v8.21.0 (#634)

This PR contains the following updates:

| Package | Change |
[Age](https://docs.renovatebot.com/merge-confidence/) |
[Adoption](https://docs.renovatebot.com/merge-confidence/) |
[Passing](https://docs.renovatebot.com/merge-confidence/) |
[Confidence](https://docs.renovatebot.com/merge-confidence/) |
|---|---|---|---|---|---|
| [pg](https://redirect.github.com/brianc/node-postgres)
([source](https://redirect.github.com/brianc/node-postgres/tree/HEAD/packages/pg))
| [`8.20.0` →
`8.21.0`](https://renovatebot.com/diffs/npm/pg/8.20.0/8.21.0) |
![age](https://developer.mend.io/api/mc/badges/age/npm/pg/8.21.0?slim=true)
|
![adoption](https://developer.mend.io/api/mc/badges/adoption/npm/pg/8.21.0?slim=true)
|
![passing](https://developer.mend.io/api/mc/badges/compatibility/npm/pg/8.20.0/8.21.0?slim=true)
|
![confidence](https://developer.mend.io/api/mc/badges/confidence/npm/pg/8.20.0/8.21.0?slim=true)
|

---

### Release Notes

<details>
<summary>brianc/node-postgres (pg)</summary>

###
[`v8.21.0`](https://redirect.github.com/brianc/node-postgres/blob/HEAD/CHANGELOG.md#pg8210)

[Compare
Source](https://redirect.github.com/brianc/node-postgres/compare/pg@8.20.0...pg@8.21.0)

- Handle [SASL
SCRAM](https://redirect.github.com/brianc/node-postgres/pull/3521)
server error responses properly.
- Add support for
[node@26](https://redirect.github.com/brianc/node-postgres/pull/3667).
- Add `scramMaxIterations` [config
option](https://redirect.github.com/brianc/node-postgres/pull/3677).
- Add `client.getTransactionStatus()`
[method](https://redirect.github.com/brianc/node-postgres/pull/3645).

</details>

---

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package.json

@@ -26,7 +26,7 @@
     "helmet": "8.1.0",
     "koa": "3.2.0",
     "koa-compress": "5.2.1",
-    "pg": "8.20.0",
+    "pg": "8.21.0",
     "postgraphile": "4.14.1"
   },
   "// build": "Dependencies required to build the project",