Update canvas dependency version to 3.2.0

This adds support for newer nodejs versions.

Author: paladox

package.json

@@ -41,7 +41,7 @@
         ]
     },
     "optionalDependencies": {
-        "canvas": "2.11.2"
+        "canvas": "3.2.0"
     },
     "devDependencies": {
         "chai": "^4.3.7",