fix(deps): update dependency postcss-loader to v8 (#1091)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

packages/react-scripts/package.json

@@ -71,7 +71,7 @@
     "mini-css-extract-plugin": "^2.7.7",
     "postcss": "^8.4.33",
     "postcss-flexbugs-fixes": "^5.0.2",
-    "postcss-loader": "^7.3.4",
+    "postcss-loader": "^8.0.0",
     "postcss-normalize": "^10.0.1",
     "postcss-preset-env": "^9.3.0",
     "prettier": "^3.2.4",

yarn.lock

@@ -4351,7 +4351,7 @@ __metadata:
     mini-css-extract-plugin: "npm:^2.7.7"
     postcss: "npm:^8.4.33"
     postcss-flexbugs-fixes: "npm:^5.0.2"
-    postcss-loader: "npm:^7.3.4"
+    postcss-loader: "npm:^8.0.0"
     postcss-normalize: "npm:^10.0.1"
     postcss-preset-env: "npm:^9.3.0"
     prettier: "npm:^3.2.4"
@@ -18344,7 +18344,7 @@ __metadata:
   languageName: node
   linkType: hard
 
-"postcss-loader@npm:^7.3.3, postcss-loader@npm:^7.3.4":
+"postcss-loader@npm:^7.3.3":
   version: 7.3.4
   resolution: "postcss-loader@npm:7.3.4"
   dependencies:
@@ -18358,6 +18358,20 @@ __metadata:
   languageName: node
   linkType: hard
 
+"postcss-loader@npm:^8.0.0":
+  version: 8.0.0
+  resolution: "postcss-loader@npm:8.0.0"
+  dependencies:
+    cosmiconfig: "npm:^9.0.0"
+    jiti: "npm:^1.20.0"
+    semver: "npm:^7.5.4"
+  peerDependencies:
+    postcss: ^7.0.0 || ^8.0.1
+    webpack: ^5.0.0
+  checksum: a31eedd2cac3a46b60527a2aee2369010f65dfc1dafb6ee00badfe6b662cefe00269b03adaa04be1524c566ea5b00f8716c150e79fe9b5c4fc8bb39a4e372be1
+  languageName: node
+  linkType: hard
+
 "postcss-logical@npm:^7.0.0":
   version: 7.0.0
   resolution: "postcss-logical@npm:7.0.0"