Bump stylelint, stylelint-config-gds and stylelint-order (#927)

* Bump stylelint, stylelint-config-gds and stylelint-order

Bumps [stylelint](https://github.com/stylelint/stylelint), [stylelint-config-gds](https://github.com/alphagov/stylelint-config-gds) and [stylelint-order](https://github.com/hudochenkov/stylelint-order). These dependencies needed to be updated together.

Updates `stylelint` from 13.13.1 to 14.6.1
- [Release notes](https://github.com/stylelint/stylelint/releases)
- [Changelog](https://github.com/stylelint/stylelint/blob/main/CHANGELOG.md)
- [Commits](stylelint/stylelint@13.13.1...14.6.1)

Updates `stylelint-config-gds` from 0.1.0 to 0.2.0
- [Release notes](https://github.com/alphagov/stylelint-config-gds/releases)
- [Changelog](https://github.com/alphagov/stylelint-config-gds/blob/main/CHANGELOG.md)
- [Commits](alphagov/stylelint-config-gds@0.1.0...0.2.0)

Updates `stylelint-order` from 4.1.0 to 5.0.0
- [Release notes](https://github.com/hudochenkov/stylelint-order/releases)
- [Changelog](https://github.com/hudochenkov/stylelint-order/blob/master/CHANGELOG.md)
- [Commits](hudochenkov/stylelint-order@4.1.0...5.0.0)

---
updated-dependencies:
- dependency-name: stylelint
  dependency-type: direct:development
  update-type: version-update:semver-major
- dependency-name: stylelint-config-gds
  dependency-type: direct:development
  update-type: version-update:semver-minor
- dependency-name: stylelint-order
  dependency-type: direct:development
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

* Explicitly add postcss to dependencies
stylelint-config-gds includes postcss-scss, this expects postcss as peer
depdendency, by default, other dependencies use the wrong version. Needed
to install as dependency so that the correct version is available. More
info here:
stylelint-scss/stylelint-config-standard-scss#5

* Fixed stylelint issues in phase banner

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: ivanELEC <ivan.yohuno@digital.justice.gov.uk>

app/webpack/stylesheets/components/_phase_banner.scss

@@ -1,7 +1,7 @@
-$app-uat-colour: govuk-colour('orange');
-$app-staging-colour: govuk-colour('turquoise');
-$app-dev-colour: govuk-colour('pink');
-$app-local-colour: govuk-colour('bright-purple');
+$app-uat-colour: govuk-colour("orange");
+$app-staging-colour: govuk-colour("turquoise");
+$app-dev-colour: govuk-colour("pink");
+$app-local-colour: govuk-colour("bright-purple");
 
 .app-environment-uat {
   .govuk-header__container {

package.json

@@ -11,13 +11,14 @@
     "@rails/ujs": "^7.0.2",
     "@rails/webpacker": "5.4.3",
     "govuk-frontend": "^4.0.1",
-    "jquery": "3.6.0"
+    "jquery": "3.6.0",
+    "postcss": "^8.4.12"
   },
   "devDependencies": {
     "standard": "^16.0.4",
-    "stylelint": "^13.13.1",
-    "stylelint-config-gds": "^0.1.0",
-    "stylelint-order": "^4.1.0",
+    "stylelint": "^14.6.1",
+    "stylelint-config-gds": "^0.2.0",
+    "stylelint-order": "^5.0.0",
     "webpack-dev-server": "^4.7.4"
   },
   "resolutions": {