Bump postcss from 8.2.15 to 8.3.0 in /build/javascript (#1033)

Bumps [postcss](https://github.com/postcss/postcss) from 8.2.15 to 8.3.0.
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](https://github.com/postcss/postcss/compare/8.2.15...8.3.0)

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

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

build/javascript/package-lock.json

@@ -1480,14 +1480,14 @@
       }
     },
     "postcss": {
-      "version": "8.2.15",
-      "resolved": "https://registry.npmjs.org/postcss/-/postcss-8.2.15.tgz",
-      "integrity": "sha512-2zO3b26eJD/8rb106Qu2o7Qgg52ND5HPjcyQiK2B98O388h43A448LCslC0dI2P97wCAQRJsFvwTRcXxTKds+Q==",
+      "version": "8.3.0",
+      "resolved": "https://registry.npmjs.org/postcss/-/postcss-8.3.0.tgz",
+      "integrity": "sha512-+ogXpdAjWGa+fdYY5BQ96V/6tAo+TdSSIMP5huJBIygdWwKtVoB5JWZ7yUd4xZ8r+8Kvvx4nyg/PQ071H4UtcQ==",
       "dev": true,
       "requires": {
         "colorette": "^1.2.2",
         "nanoid": "^3.1.23",
-        "source-map": "^0.6.1"
+        "source-map-js": "^0.6.2"
       },
       "dependencies": {
         "colorette": {
@@ -2438,6 +2438,12 @@
       "resolved": "https://registry.npmjs.org/source-map/-/source-map-0.6.1.tgz",
       "integrity": "sha512-UjgapumWlbMhkBgzT7Ykc5YXUT46F0iKu8SGXq0bcwP5dz/h0Plj6enJqjz1Zbq2l5WaqYnrVbwWOWMyF3F47g=="
     },
+    "source-map-js": {
+      "version": "0.6.2",
+      "resolved": "https://registry.npmjs.org/source-map-js/-/source-map-js-0.6.2.tgz",
+      "integrity": "sha512-/3GptzWzu0+0MBQFrDKzw/DvvMTUORvgY6k6jd/VS6iCR4RDTKWH6v6WPwQoUO8667uQEf9Oe38DxAYWY5F/Ug==",
+      "dev": true
+    },
     "sourcemap-codec": {
       "version": "1.4.8",
       "resolved": "https://registry.npmjs.org/sourcemap-codec/-/sourcemap-codec-1.4.8.tgz",

build/javascript/package.json

@@ -16,7 +16,7 @@
   },
   "devDependencies": {
     "cssnano": "^5.0.3",
-    "postcss": "^8.2.15",
+    "postcss": "^8.3.0",
     "postcss-cli": "^8.3.1"
   },
   "snowpack": {