Update dependency postcss-loader to v7 (#49237)

Co-authored-by: Renovate Bot <bot@renovateapp.com>

package.json

@@ -215,7 +215,7 @@
     "node-notifier": "10.0.1",
     "nodemon": "2.0.15",
     "postcss": "8.4.12",
-    "postcss-loader": "6.2.1",
+    "postcss-loader": "7.0.0",
     "postcss-reporter": "7.0.5",
     "postcss-scss": "4.0.3",
     "prettier": "2.6.0",

packages/grafana-ui/package.json

@@ -159,7 +159,7 @@
     "expose-loader": "4.0.0",
     "mock-raf": "1.0.1",
     "postcss": "8.4.12",
-    "postcss-loader": "6.2.1",
+    "postcss-loader": "7.0.0",
     "process": "^0.11.10",
     "raw-loader": "4.0.2",
     "react-docgen-typescript-loader": "3.7.2",

yarn.lock

@@ -4808,7 +4808,7 @@ __metadata:
     monaco-editor: ^0.31.1
     ol: 6.14.1
     postcss: 8.4.12
-    postcss-loader: 6.2.1
+    postcss-loader: 7.0.0
     prismjs: 1.28.0
     process: ^0.11.10
     raw-loader: 4.0.2
@@ -21299,7 +21299,7 @@ __metadata:
     papaparse: 5.3.2
     pluralize: ^8.0.0
     postcss: 8.4.12
-    postcss-loader: 6.2.1
+    postcss-loader: 7.0.0
     postcss-reporter: 7.0.5
     postcss-scss: 4.0.3
     prettier: 2.6.0
@@ -29440,17 +29440,17 @@ __metadata:
   languageName: node
   linkType: hard
 
-"postcss-loader@npm:6.2.1":
-  version: 6.2.1
-  resolution: "postcss-loader@npm:6.2.1"
+"postcss-loader@npm:7.0.0":
+  version: 7.0.0
+  resolution: "postcss-loader@npm:7.0.0"
   dependencies:
     cosmiconfig: ^7.0.0
     klona: ^2.0.5
-    semver: ^7.3.5
+    semver: ^7.3.7
   peerDependencies:
     postcss: ^7.0.0 || ^8.0.1
     webpack: ^5.0.0
-  checksum: e40ae79c3e39df37014677a817b001bd115d8b10dedf53a07b97513d93b1533cd702d7a48831bdd77b9a9484b1ec84a5d4a723f80e83fb28682c75b5e65e8a90
+  checksum: b8e51e99898cae8400de8690752b64af2ca1e3eed7c0d696c9e1ec6fc45dd334c958748247632c48109a519fb59f7545d0b8fe4b52479d982ca3ec4eb8e3b0c9
   languageName: node
   linkType: hard