Add mjml parser (#17339)

scripts/utils/changelog-categories.js

@@ -11,6 +11,7 @@ export const CHANGELOG_CATEGORIES = [
   "json",
   "less",
   "lwc",
+  "mjml",
   "markdown",
   "mdx",
   "scss",

scripts/utils/changelog.js

@@ -22,6 +22,7 @@ export const categories = [
   { dir: "vue", title: "Vue" },
   { dir: "angular", title: "Angular" },
   { dir: "lwc", title: "LWC" },
+  { dir: "mjml", title: "MJML" },
   { dir: "handlebars", title: "Ember / Handlebars" },
   { dir: "graphql", title: "GraphQL" },
   { dir: "markdown", title: "Markdown" },