chore(deps-dev): bump postcss-loader in /src/packages/excalidraw (#3788)

Bumps [postcss-loader](https://github.com/webpack-contrib/postcss-loader) from 6.1.0 to 6.1.1.
- [Release notes](https://github.com/webpack-contrib/postcss-loader/releases)
- [Changelog](https://github.com/webpack-contrib/postcss-loader/blob/master/CHANGELOG.md)
- [Commits](https://github.com/webpack-contrib/postcss-loader/compare/v6.1.0...v6.1.1)

---
updated-dependencies:
- dependency-name: postcss-loader
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

src/packages/excalidraw/package.json

     "css-loader": "5.2.6",
     "file-loader": "6.2.0",
     "mini-css-extract-plugin": "1.6.1",
-    "postcss-loader": "6.1.0",
+    "postcss-loader": "6.1.1",
     "sass-loader": "12.1.0",
     "terser-webpack-plugin": "5.1.4",
     "ts-loader": "9.2.3",

src/packages/excalidraw/yarn.lock

   dependencies:
     find-up "^4.0.0"
 
-postcss-loader@6.1.0:
-  version "6.1.0"
-  resolved "https://registry.yarnpkg.com/postcss-loader/-/postcss-loader-6.1.0.tgz#13c800a00b3c7d434a1319a73d85e2df0714cdde"
-  integrity sha512-yA/cXBfACkthZNA2hQxOnaReVfQ6uLmvbEDQzNafpbK40URZJvP/28dL1DG174Gvz3ptkkHbbwDBCh+gXR94CA==
+postcss-loader@6.1.1:
+  version "6.1.1"
+  resolved "https://registry.yarnpkg.com/postcss-loader/-/postcss-loader-6.1.1.tgz#58dd0a3accd9bc87cc52eff75244db578d11301a"
+  integrity sha512-lBmJMvRh1D40dqpWKr9Rpygwxn8M74U9uaCSeYGNKLGInbk9mXBt1ultHf2dH9Ghk6Ue4UXlXWwGMH9QdUJ5ug==
   dependencies:
     cosmiconfig "^7.0.0"
     klona "^2.0.4"