ci: bump node.js runtime version

[luislhl]

Acceptance Criteria

• CodeBuild should use Node.js 16 as runtime to build and deploy the project
• We should use npm ci in the build, instead of npm install

TODO

• Make sure CodeBuild uses a newer Docker image that supports Node.js 16

Checklist

• If you are requesting a merge into master, confirm this code is production-ready and can be included in future releases as soon as it gets merged
• Make sure either the unit tests and/or the QA tests are capable of testing the new features
• Make sure you do not include new dependencies in the project unless strictly necessary and do not include dev-dependencies as production ones. More dependencies increase the possibility of one of them being hijacked and affecting us.

[codecov]

Codecov Report

Merging #437 (d1ad798) into master (d662883) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #437   +/-   ##
=======================================
  Coverage   95.60%   95.60%           
=======================================
  Files          40       40           
  Lines        2458     2458           
  Branches      278      278           
=======================================
  Hits         2350     2350           
  Misses        108      108