ci(lint): Replace deprecated Stylelint Github formatter with a Github problem matcher.

.github/problem-matchers/stylelint.json

@@ -0,0 +1,21 @@
+{
+  "problemMatcher": [
+    {
+      "owner": "stylelint",
+      "pattern": [
+        {
+          "regexp": "^([^\\s].*)$",
+          "file": 1
+        },
+        {
+          "regexp": "^\\s*(\\d+):(\\d+)\\s+(\\S+)\\s+(.+?)\\s+(\\S+)$",
+          "line": 1,
+          "column": 2,
+          "message": 4,
+          "code": 5,
+          "loop": true
+        }
+      ]
+    }
+  ]
+}

.github/workflows/lint.yaml

@@ -29,4 +29,13 @@ jobs:
         with:
           node-version: 22
       - run: "npm clean-install"
-      - run: "npm run lint:ci"
+      - name: "Set up Stylelint Problem Matcher"
+        run: "echo '::add-matcher::./.github/problem-matchers/stylelint.json'"
+      - name: "Run `lint:ci` script."
+        run: |-
+          # Disable ANSI color codes in Stylelint default "string" formatter
+          export NO_COLOR=1
+          npm run lint:ci
+      - if: "always()"
+        name: "Remove Stylelint Problem Matcher"
+        run: "echo '::remove-matcher::./.github/problem-matchers/stylelint.json'"

package.json

@@ -11,7 +11,7 @@
     "lint:check": "npm-run-all --sequential --continue-on-error lint:check:*",
     "lint:check:css": "stylelint src/**/*.css",
     "lint:check:js": "eslint src webpack.*.js --max-warnings 0",
-    "lint:ci": "npm-run-all --sequential --continue-on-error lint:check:js \"lint:check:css -- --formatter github\"",
+    "lint:ci": "npm-run-all --sequential --continue-on-error lint:check:*",
     "lint:fix": "npm-run-all --parallel --continue-on-error \"lint:check:* -- --fix\""
   },
   "repository": {