docs(aio): add my details as a contributor (#18315)

PR Close #18315

aio/content/marketing/contributors.json

@@ -573,5 +573,14 @@
    "website": "http://www.methotic.com",
    "bio": "Thierry is a senior consultant and trainer, specialized on Angular, and a Google Developer Expert.",
    "group": "GDE"
+ },
+
+"gerardsans": {
+   "name": "Gerard Sans",
+   "picture": "gerardsans.jpg",
+   "twitter": "gerardsans",
+   "website": "https://medium.com/@gerard.sans",
+   "bio": "Gerard is very excited about the future of the Web and JavaScript. Always happy Computer Science Engineer and humble Google Developer Expert. He loves to share his learnings by giving talks, trainings and writing about cool technologies. He loves running AngularZone and GraphQL London, mentoring students and giving back to the community.",
+   "group": "GDE"
  }
 }