fix(icon-button): centre icon (#828)

* fix(icon-button): add flex to center icon

Author: montezume

.size-snapshot.json

@@ -1,15 +1,15 @@
 {
   "dist/ui-kit.esm.js": {
-    "bundled": 866794,
-    "minified": 596086,
-    "gzipped": 121167,
+    "bundled": 866786,
+    "minified": 596078,
+    "gzipped": 121176,
     "treeshaked": {
       "rollup": {
-        "code": 429620,
+        "code": 429612,
         "import_statements": 919
       },
       "webpack": {
-        "code": 453947
+        "code": 453939
       }
     }
   }

src/components/buttons/icon-button/icon-button.js

@@ -48,8 +48,8 @@ export const IconButton = props => {
       onMouseOut={props.handleMouseOut}
       css={[
         css`
+          display: flex;
           border: 1px solid ${vars.colorSurface};
-          display: inline-block;
           background-color: ${vars.colorSurface};
           box-shadow: ${vars.shadow7};
           color: ${vars.colorSolid};