update icon: postcss (original, original-wordmark, plain-wordmark) (#2012)

* Update postcss icon

* Fix color

* Fix icon

* Update optimized svg

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Co-authored-by: Jørgen Kalsnes Hagen <43886029+Snailedlt@users.noreply.github.com>

devicon.json

@@ -7637,16 +7637,20 @@
             "svg": [
                 "original",
                 "original-wordmark",
-                "plain",
                 "plain-wordmark"
             ],
             "font": [
-                "plain",
+                "original",
                 "plain-wordmark"
             ]
         },
-        "color": "#dd3735",
-        "aliases": []
+        "color": "#DD3A0A",
+        "aliases": [
+            {
+                "base": "original",
+                "alias": "plain"
+            }
+        ]
     },
     {
         "name": "postgresql",