Update json-fortran?

[aekiss]

https://github.com/jacobwilliams/json-fortran has had quite a few commits recently, and is now at release 8.0.0 - do we want to upgrade the version we use?

[aekiss]

I upgraded to 8.0.0 in commit 4942b6a

[aekiss]

Looks like PR #51 was never merged, so I'm not sure why I closed this issue.

https://github.com/jacobwilliams/json-fortran development is continuing apace.

Our master is still using a version from over 2 years ago, now over 100 commits behind the latest. Should we upgrade?

[aekiss]

PR #51 is also quite out of date now (8.0.0; latest release is 8.2.3)

[aekiss]

... now the latest is 8.2.4

[aekiss]

Or consider this PR that updates both json-fortran and datetime-fortran #71