Version 1.13.0 of gtest requires C++14

[musicinmybrain]

The latest version of gtest (1.13.0) requires C++14, but easyloggingpp compiles and runs its tests as C++11.

In file included from /usr/include/gtest/gtest-message.h:57,
                 from /usr/include/gtest/gtest-assertion-result.h:46,
                 from /usr/include/gtest/gtest.h:64,
                 from /builddir/build/BUILD/easyloggingpp-8489989bb26c6371df103f6cbced3fbee1bc3c2f/test/test.h:11,
                 from /builddir/build/BUILD/easyloggingpp-8489989bb26c6371df103f6cbced3fbee1bc3c2f/test/main.cc:3:
/usr/include/gtest/internal/gtest-port.h:270:2: error: #error C++ versions less than C++14 are not supported.
  270 | #error C++ versions less than C++14 are not supported.
      |  ^~~~~

This will be increasingly problematic for some users. For example, Linux distribution packages working with system copies of gtest will have to patch the tests to use C++14. (I maintain the easyloggingpp package in Fedora Linux).

Presumably you would stop claiming C++11 support if you stop testing it. Is there a plan to do this, moving forward to C++14 as the new minimum? Any other suggestions?

Thanks.