googletest: update to 1.12.1.

1.12.1

C++ Language Support

    This will be the last release to support C++11. Future releases will require at least C++14.

Mocking

    Support for move-only values to Return (5126f71)

Matchers

    New matchers
        WhenBase64Unescaped (652ec31)
    ResultOf() now has a 3-arg overload that takes a description string for better error messages (0e40217)

Build & Test

    CMake minimum increased to 3.5
    Bazel users that build GoogleTest using the Abseil library as a dependency now also require a dependency on RE2 (e33c2b2)
    Bazel users that build GoogleTest using the Abseil library now use the Abseil library to parse all command-line flags (25dcdc7)

Patches

58d77fa - Fixes the version number in CMakeLists.txt (#3911)

(wiz)