Fix Conan Example

[csegarragonz]

As mentioned in a related issue, the Conan example is broken. It uses version 0.4.0 that still installs picojson/1.3.0 as a dependency.

For code versions greater than 0.5.0, picojson is no longer installed as a dependency, and the provided example fails to build.

In this PR I provide a minimal fix, but you may prefer to change the Conan recipe altogether.

[prince-chrismc]

As mentioned in a related issue,

Sorry for not responding, I am "taking time off" so I was not able to answer #213 (comment)

But I am very glad you found the issue! I am super grateful you've gone above and beyond to contribute back and improve our example! 🚀 💟

picojson is no longer installed as a dependency... but you may prefer to change the Conan recipe altogether.

There a lot of context behind it but this is the intended usage... conan-io/conan-center-index#4644 (comment)