message: Fix some link issues in the `README.md`.
diff: [![Coverage](https://codecov.io/gh/ginkgo-project/ginkgo/branch/develop/graph/badge.svg)](https://codecov.io/gh/ginkgo-project/ginkgo)
  [![CDash dashboard](https://img.shields.io/badge/CDash-Access-blue.svg)](http://my.cdash.org/index.php?project=Ginkgo+Project)
  [![Documentation](https://img.shields.io/badge/Documentation-latest-blue.svg)](https://ginkgo-project.github.io/ginkgo/doc/develop/)
  -[![License](https://img.shields.io/github/license/ginkgo-project/ginkgo.svg)](LICENSE)
  +[![License](https://img.shields.io/github/license/ginkgo-project/ginkgo.svg)](./LICENSE)
  [![c++ standard](https://img.shields.io/badge/c%2B%2B-11-blue.svg)](https://en.wikipedia.org/wiki/C%2B%2B#Standardization)
  Ginkgo is a high-performance linear algebra library for manycore systems, with a
  @@ -93,7 +93,7 @@ Ginkgo does comprehensive unit tests using Google Tests. These tests are enabled
  A unique feature of Ginkgo is the ability to run benchmarks and view your results
  with the help of the [Ginkgo Performance Explorer (GPE)](https://ginkgo-project.github.io/gpe/).
  -More details about this can be found in the [documentation](https://ginkgo-project.github.io/ginkgo/doc/master/)
  +More details about this can be found in the [BENCHMARKING.md page](./BENCHMARKING.md)
  Contributing to Ginkgo
  ---------------------------
  @@ -105,7 +105,7 @@ external contributors like in the example below.
  #### Contributors
  I hereby place all my contributions in this codebase under a BSD-3-Clause
  -license, as specified in the repository's [LICENSE](LICENSE) file.
  +license, as specified in the repository's [LICENSE](./LICENSE) file.
  Name Surname <email@domain> Institution(s)
  