Merge pull request cerebral#432 from cerebral/dependabot/npm_and_yarn/prismjs-1.21.0

chore(deps): bump prismjs from 1.15.0 to 1.21.0

Author: christianalfoni

package-lock.json

@@ -50,7 +50,7 @@
     "phoenix": "1.4.13",
     "preact": "8.3.1",
     "preact-compat": "3.18.4",
-    "prismjs": "1.15.0",
+    "prismjs": "1.21.0",
     "query-string": "6.2.0",
     "react": "16.9.0",
     "react-dom": "16.9.0",