Center canvas of interpreter outputs (#227)

* Center canvas in repl history

* Bump version v0.1.5 -> v0.1.6

Author: ning-y

package.json

@@ -1,7 +1,7 @@
 {
   "private": true,
   "name": "cadet-frontend",
-  "version": "0.1.5",
+  "version": "0.1.6",
   "scripts-info": {
     "format": "Format source code",
     "start": "Start the Webpack development server",

src/styles/_workspace.scss

@@ -240,6 +240,18 @@ $code-color-error: #ff4444;
 
       .resultOutput {
         color: $code-color-result;
+
+        .canvas-container {
+          display: flex;
+          padding: 0.5rem 0 0.5rem 0;
+          align-items: center;
+          justify-content: center;
+        }
+
+        canvas {
+          height: 20rem;
+          width: 20rem;
+        }
       }
 
       .errorOutput {