feat(DF-903) update model version (#336)

* feat(DF-903): Add linkAttributes extension to engine markdown parser

Add the linkAttributes inline extension to consume {:target="_blank"}
syntax so it is not rendered as plain text in check answers summaries.
Also add linkAttributes to the allowed token types whitelist.

* chore: update @defra/forms-model dependency to version 3.0.637 in package.json and package-lock.json

* revert: remove linkAttributes extension from engine markdown parser

This parser is only used for check answers summaries which render
user-entered field values — {:target="_blank"} syntax will not
appear there. The extension is only needed in the model's
markdownToHtml which handles designer-authored content.

Author: mokhld

package-lock.json

@@ -82,7 +82,7 @@
   },
   "license": "SEE LICENSE IN LICENSE",
   "dependencies": {
-    "@defra/forms-model": "^3.0.627",
+    "@defra/forms-model": "^3.0.637",
     "@defra/hapi-tracing": "^1.29.0",
     "@defra/interactive-map": "^0.0.4-alpha",
     "@elastic/ecs-pino-format": "^1.5.0",