Rename CODE_OF_CONDUCT.md to CODE_OF_CONDUCT.md yared Tura

@yarukalove5 <!-- IMPORTANT: Please do not create a Pull Request without creating an issue first. Read the Guidelines, If you haven't done it yet. https://github.com/webcompat/webcompat.com/blob/master/docs/pr-coding-guidelines.md --> This PR fixes issue #nnnn ## Proposed PR background Please provide enough information so that others can review your pull request: