Updated year in README.md

[jef]

Updates the README from 2018 to 2019

Happy New Year 🎉

Pull request checklist

Read the Contribution Guidelines for detailed information.

• Changes are described in the pull request, or an existing issue is referenced.
• The test suite compiles and runs without error.
• Code coverage is 100%. Test cases can be added by editing the test suite.
• The source code is amalgamated; that is, after making changes to the sources in the include/nlohmann directory, run make amalgamate to create the single-header file single_include/nlohmann/json.hpp. The whole process is described here.

[coveralls]

Coverage remained the same at 100.0% when pulling 7f73915 on hijxf:patch-1 into df460c9 on nlohmann:develop.

[nickaein]

There is another 2018 reference in very last lines of README.md in copyright note. Is there any reason to update/not update it?

There is also other references to 2018 throughout the code that should be considered.

[nlohmann]

No need to update the copyright years. I will do this with the next release.

[nlohmann]

Looks good to me.

[jef]

Awesome. Thanks!

[jef]

Accidentally closed.

Thanks,
Jef

[nlohmann]

Thanks!