OSSFuzz integration

[capuanob]

What does this change do?

• Introduces a fuzzing directory containing a fuzzing harness that targets the parse entrypoint and tests the various serializers available in the library.
• Introduces a build script that the OSSFuzz integration will use to build the fuzzer twice a day
• Integrates the fuzzer into the build-system, using a CMake Option called BUILD_FUZZER

Is it related to an exisiting bug report or feature request?

Implements #208

Pre-merge checklist

• I've read CONTRIBUTING.md
• I've rebased my changes against the current HEAD of origin/master (if necessary)
• I've added new test cases to verify my change
• I've regenerated toml.hpp (how-to)
• I've updated any affected documentation
• I've rebuilt and run the tests with at least one of:
  • Clang 8 or higher
  • GCC 8 or higher
  • MSVC 19.20 (Visual Studio 2019) or higher
• I've added my name to the list of contributors in README.md

[capuanob]

@marzer Apologize for the delay in getting this implemented! This PR represents the majority of what is needed to get this project integrated into OSSFuzz for continuous fuzz-testing. Once this is merged, I will submit a PR to the OSSFuzz project that defines a Dockerfile that will pull this project and run the build.sh

[capuanob]

@marzer Apologize for the delay in getting this implemented! This PR represents the majority of what is needed to get this project integrated into OSSFuzz for continuous fuzz-testing. Once this is merged, I will submit a PR to the OSSFuzz project that defines a Dockerfile that will pull this project and run the build.sh

Also, the CIFuzz job will fail until that Dockerfile is merged into OSSFuzz

[marzer]

Thanks for this! Looks good to me :)

Also, the CIFuzz job will fail until that Dockerfile is merged into OSSFuzz

Yep, figured as much. No problem.