Update dependency postcss to v8.4.0

package.json

@@ -56,7 +56,7 @@
         "gulp-util": "3.0.8",
         "gulp-watch": "5.0.1",
         "gulp-zip": "5.1.0",
-        "postcss": "8.3.11",
+        "postcss": "8.4.0",
         "postcss-color-mod-function": "3.0.3",
         "postcss-easy-import": "3.0.0"
     },

yarn.lock

@@ -4100,14 +4100,14 @@ postcss-values-parser@^2.0.0:
     indexes-of "^1.0.1"
     uniq "^1.0.1"
 
-postcss@8.3.11:
-  version "8.3.11"
-  resolved "https://registry.yarnpkg.com/postcss/-/postcss-8.3.11.tgz#c3beca7ea811cd5e1c4a3ec6d2e7599ef1f8f858"
-  integrity sha512-hCmlUAIlUiav8Xdqw3Io4LcpA1DOt7h3LSTAC4G6JGHFFaWzI6qvFt9oilvl8BmkbBRX1IhM90ZAmpk68zccQA==
+postcss@8.4.0:
+  version "8.4.0"
+  resolved "https://registry.yarnpkg.com/postcss/-/postcss-8.4.0.tgz#cd4c33af00a00ba93ccf6ae1219f57c5e5ab5234"
+  integrity sha512-BRMNx3Wy7UI89jN8H4ZVS5lQMPM2OSMkOkvDCSjwXa7PWTs24k7Lm55NXLbMbs070LvraXaxN5l1npSOS6wMVw==
   dependencies:
     nanoid "^3.1.30"
     picocolors "^1.0.0"
-    source-map-js "^0.6.2"
+    source-map-js "^1.0.1"
 
 postcss@^6.0.1, postcss@^6.0.11:
   version "6.0.23"
@@ -4641,10 +4641,10 @@ snapdragon@^0.8.1:
     source-map-resolve "^0.5.0"
     use "^3.1.0"
 
-source-map-js@^0.6.2:
-  version "0.6.2"
-  resolved "https://registry.yarnpkg.com/source-map-js/-/source-map-js-0.6.2.tgz#0bb5de631b41cfbda6cfba8bd05a80efdfd2385e"
-  integrity sha512-/3GptzWzu0+0MBQFrDKzw/DvvMTUORvgY6k6jd/VS6iCR4RDTKWH6v6WPwQoUO8667uQEf9Oe38DxAYWY5F/Ug==
+source-map-js@^1.0.1:
+  version "1.0.1"
+  resolved "https://registry.yarnpkg.com/source-map-js/-/source-map-js-1.0.1.tgz#a1741c131e3c77d048252adfa24e23b908670caf"
+  integrity sha512-4+TN2b3tqOCd/kaGRJ/sTYA0tR0mdXx26ipdolxcwtJVqEnqNYvlCAt1q3ypy4QMlYus+Zh34RNtYLoq2oQ4IA==
 
 source-map-resolve@^0.5.0:
   version "0.5.3"