Analyze the package with RcppDeepState

[FabrizioSandri]

This PR adds a new Github Action which runs RcppDeepState+valgrind on your package. That means the C++ functions of your package will be tested with random inputs, and there will be a comment like this one for each new PR (which reports if valgrind found any issues with random inputs).

RcppDeepState analysis result

This package contains problems, according to RcppDeepState. The report was generated by RcppDeepState-action in this repository's fork and is accessible here.