chore(deps): update font awesome to v6

Author: renovate[bot]

package-lock.json

@@ -31,8 +31,8 @@
   "devDependencies": {
     "@edx/browserslist-config": "^1.1.1",
     "@edx/stylelint-config-edx": "2.3.0",
-    "@fortawesome/fontawesome-svg-core": "1.2.36",
-    "@fortawesome/free-solid-svg-icons": "5.15.4",
+    "@fortawesome/fontawesome-svg-core": "6.4.0",
+    "@fortawesome/free-solid-svg-icons": "6.4.0",
     "@fortawesome/react-fontawesome": "0.2.0",
     "chroma-js": "2.4.2",
     "classnames": "2.3.2",