build: update postcss to version 7.0.18

Author: renovate-bot

packages/angular_devkit/build_angular/package.json

@@ -36,7 +36,7 @@
     "minimatch": "3.0.4",
     "parse5": "4.0.0",
     "open": "6.4.0",
-    "postcss": "7.0.17",
+    "postcss": "7.0.18",
     "postcss-import": "12.0.1",
     "postcss-loader": "3.0.0",
     "raw-loader": "3.1.0",

yarn.lock

@@ -9050,10 +9050,10 @@ postcss-value-parser@^4.0.0:
   resolved "https://registry.yarnpkg.com/postcss-value-parser/-/postcss-value-parser-4.0.0.tgz#99a983d365f7b2ad8d0f9b8c3094926eab4b936d"
   integrity sha512-ESPktioptiSUchCKgggAkzdmkgzKfmp0EU8jXH+5kbIUB+unr0Y4CY9SRMvibuvYUBjNh1ACLbxqYNpdTQOteQ==
 
-[email protected].17, postcss@^7.0.17:
-  version "7.0.17"
-  resolved "https://registry.yarnpkg.com/postcss/-/postcss-7.0.17.tgz#4da1bdff5322d4a0acaab4d87f3e782436bad31f"
-  integrity sha512-546ZowA+KZ3OasvQZHsbuEpysvwTZNGJv9EfyCQdsIDltPSWHAeTQ5fQy/Npi2ZDtLI3zs7Ps/p6wThErhm9fQ==
+[email protected].18:
+  version "7.0.18"
+  resolved "https://registry.yarnpkg.com/postcss/-/postcss-7.0.18.tgz#4b9cda95ae6c069c67a4d933029eddd4838ac233"
+  integrity sha512-/7g1QXXgegpF+9GJj4iN7ChGF40sYuGYJ8WZu8DZWnmhQ/G36hfdk3q9LBJmoK+lZ+yzZ5KYpOoxq7LF1BxE8g==
   dependencies:
     chalk "^2.4.2"
     source-map "^0.6.1"
@@ -9068,6 +9068,15 @@ postcss@^7.0.0, postcss@^7.0.1, postcss@^7.0.2:
     source-map "^0.6.1"
     supports-color "^5.5.0"
 
+postcss@^7.0.17:
+  version "7.0.17"
+  resolved "https://registry.yarnpkg.com/postcss/-/postcss-7.0.17.tgz#4da1bdff5322d4a0acaab4d87f3e782436bad31f"
+  integrity sha512-546ZowA+KZ3OasvQZHsbuEpysvwTZNGJv9EfyCQdsIDltPSWHAeTQ5fQy/Npi2ZDtLI3zs7Ps/p6wThErhm9fQ==
+  dependencies:
+    chalk "^2.4.2"
+    source-map "^0.6.1"
+    supports-color "^6.1.0"
+
 prelude-ls@~1.1.2:
   version "1.1.2"
   resolved "https://registry.yarnpkg.com/prelude-ls/-/prelude-ls-1.1.2.tgz#21932a549f5e52ffd9a827f570e04be62a97da54"