Fix npm secure warning

[ilcato]

Replaced async-request package with SuperAgent package that doesn't contains dependencies on deprecated modules or security issues.

[umbynos]

Just installed, should be working fine:

bash-5.0$ npm install node-red-contrib-arduino-iot-cloud/
npm WARN deprecated fsevents@1.2.13: fsevents 1 will break on node v14+ and could be using insecure binaries. Upgrade to fsevents 2.
npm notice created a lockfile as package-lock.json. You should commit this file.
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents@^1.2.7 (node_modules/@arduino/node-red-contrib-arduino-iot-cloud/node_modules/chokidar/node_modules/fsevents):
npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for fsevents@1.2.13: wanted {"os":"darwin","arch":"any"} (current: {"os":"linux","arch":"x64"})
npm WARN @babel/cli@7.7.4 requires a peer of @babel/core@^7.0.0-0 but none is installed. You must install peer dependencies yourself.

+ @arduino/node-red-contrib-arduino-iot-cloud@1.0.5
added 4 packages from 8 contributors in 3.313s

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[umbynos]

LGTM 🏁