Bump postcss from 8.5.5 to 8.5.6 in /pkg/sass-parser (#2607)

* Bump postcss from 8.5.5 to 8.5.6 in /pkg/sass-parser

Bumps [postcss](https://github.com/postcss/postcss) from 8.5.5 to 8.5.6.
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](postcss/postcss@8.5.5...8.5.6)

---
updated-dependencies:
- dependency-name: postcss
  dependency-version: 8.5.6
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

* fix type for StatementWithChildren

* work around type limitation for the Declaration node type

* use unknown instead of any to forcefully cast a Declaration as a StatementWithChildren

---------

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Carlos (Goodwine) <[email protected]>

Author: dependabot[bot]

pkg/sass-parser/lib/src/statement/declaration.ts

@@ -24,6 +24,7 @@ import {
 } from '.';
 import {_DeclarationWithChildren} from './declaration-internal';
 import * as sassParser from '../..';
+import {ContainerWithChildren} from 'postcss/lib/container';
 
 // TODO(nweiz): Make sure setting non-identifier strings for prop here and name
 // in GenericAtRule escapes properly.
@@ -247,6 +248,8 @@ export class Declaration
 
   /** @hidden */
   normalize(node: NewNode, sample?: postcss.Node): ChildNode[] {
-    return normalize(this as StatementWithChildren, node, sample);
+    // Casting is necessary because `_Declaration` can't extend
+    // `ContainerWithChildren` because it is a union type.
+    return normalize(this as unknown as StatementWithChildren, node, sample);
   }
 }

pkg/sass-parser/lib/src/statement/index.ts

@@ -3,6 +3,7 @@
 // https://opensource.org/licenses/MIT.
 
 import * as postcss from 'postcss';
+import {ContainerWithChildren} from 'postcss/lib/container';
 
 import {Container} from '../container';
 import {Interpolation} from '../interpolation';
@@ -178,7 +179,7 @@ export interface ContainerProps extends NodeProps {
  *
  * @category Statement
  */
-export type StatementWithChildren = postcss.Container<postcss.ChildNode> &
+export type StatementWithChildren = ContainerWithChildren &
   Container<ChildNode, NewNode> &
   AnyStatement;
 

pkg/sass-parser/package.json

@@ -31,7 +31,7 @@
     "test": "jest"
   },
   "dependencies": {
-    "postcss": "8.5.5",
+    "postcss": "8.5.6",
     "sass": "file:../../build/npm"
   },
   "devDependencies": {