Add Flotiq to the available services with GraphQL (#2251)

<!--
  Thanks for making a pull request!

  Before submitting, please read our contributing guidelines:

https://github.com/graphql/graphql.github.io/blob/source/CONTRIBUTING.md

  Have any questions?
Feel free to ask in this PR or you can also find us on the #website
channel on the GraphQL Slack (invite link available in CONTRIBUTING.md)
-->

## Description

This PR adds Flotiq Headless CMS to the available services that have a
GraphQL API

Author: CiotkaCierpienia

src/code/services/flotiq.md

@@ -0,0 +1,5 @@
+---
+name: Flotiq
+description: Headless CMS that pairs a modern content editing experience with robust content personalisation and scheduling capabilities. It delivers your content through a blazing-fast, API-first delivery using GraphQL and REST endpoints.
+url: https://flotiq.com
+---