fix: package.json & yarn.lock to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-POSTCSS-5926692

package.json

@@ -22,7 +22,7 @@
     "flowbite": "^1.5.3",
     "jquery": "^3.6.0",
     "mini-css-extract-plugin": "^2.6.1",
-    "postcss": "^8.4.17",
+    "postcss": "^8.4.31",
     "postcss-import": "^15.0.0",
     "postcss-loader": "^7.1.0",
     "sass": "^1.56.0",

yarn.lock

@@ -3011,6 +3011,11 @@ nanoid@^3.3.4:
   resolved "https://registry.yarnpkg.com/nanoid/-/nanoid-3.3.4.tgz#730b67e3cd09e2deacf03c027c81c9d9dbc5e8ab"
   integrity sha512-MqBkQh/OHTS2egovRtLk45wEyNXwF+cokD+1YPf9u5VfJiRdAiRwB2froX5Co9Rh20xs4siNPm8naNotSD6RBw==
 
+nanoid@^3.3.6:
+  version "3.3.6"
+  resolved "https://registry.yarnpkg.com/nanoid/-/nanoid-3.3.6.tgz#443380c856d6e9f9824267d960b4236ad583ea4c"
+  integrity sha512-BGcqMMJuToF7i1rt+2PWSNVnWIkGCU78jBG3RxO/bZlnZPK2Cmi2QaffxGO/2RvWi9sL+FAiRiXMgsyxQ1DIDA==
+
 [email protected]:
   version "0.6.3"
   resolved "https://registry.yarnpkg.com/negotiator/-/negotiator-0.6.3.tgz#58e323a72fedc0d6f9cd4d31fe49f51479590ccd"
@@ -3352,15 +3357,6 @@ postcss@^8.3.5, postcss@^8.4.7:
     picocolors "^1.0.0"
     source-map-js "^1.0.2"
 
-postcss@^8.4.17:
-  version "8.4.20"
-  resolved "https://registry.yarnpkg.com/postcss/-/postcss-8.4.20.tgz#64c52f509644cecad8567e949f4081d98349dc56"
-  integrity sha512-6Q04AXR1212bXr5fh03u8aAwbLxAQNGQ/Q1LNa0VfOI06ZAlhPHtQvE4OIdpj4kLThXilalPnmDSOD65DcHt+g==
-  dependencies:
-    nanoid "^3.3.4"
-    picocolors "^1.0.0"
-    source-map-js "^1.0.2"
-
 postcss@^8.4.18:
   version "8.4.18"
   resolved "https://registry.yarnpkg.com/postcss/-/postcss-8.4.18.tgz#6d50046ea7d3d66a85e0e782074e7203bc7fbca2"
@@ -3370,6 +3366,15 @@ postcss@^8.4.18:
     picocolors "^1.0.0"
     source-map-js "^1.0.2"
 
+postcss@^8.4.31:
+  version "8.4.31"
+  resolved "https://registry.yarnpkg.com/postcss/-/postcss-8.4.31.tgz#92b451050a9f914da6755af352bdc0192508656d"
+  integrity sha512-PS08Iboia9mts/2ygV3eLpY5ghnUcfLV/EXTOW1E2qYxJKGGBUtNjN76FYHnMs36RmARn41bC0AZmn+rR0OVpQ==
+  dependencies:
+    nanoid "^3.3.6"
+    picocolors "^1.0.0"
+    source-map-js "^1.0.2"
+
 pretty-hrtime@^1.0.3:
   version "1.0.3"
   resolved "https://registry.yarnpkg.com/pretty-hrtime/-/pretty-hrtime-1.0.3.tgz#b7e3ea42435a4c9b2759d99e0f201eb195802ee1"