new icon: circleci (plain, plain-wordmark) (#648)

Co-authored-by: Raúl Julián López Caña <rjlopezmad@gmail.com>
Co-authored-by: Clemens Bastian <8781699+amacado@users.noreply.github.com>

Author: 3 people

devicon.json

@@ -506,6 +506,16 @@
         "color": "#ce4e4e",
         "aliases": []
     },
+    {
+        "name": "circleci",
+        "tags": ["integration", "platform"],
+        "versions": {
+          "svg": ["plain", "plain-wordmark"],
+          "font": ["plain", "plain-wordmark"]
+        },
+        "color": "#343434",
+        "aliases": []
+    },
     {
         "name": "clojure",
         "tags": [