1.2.0 release

[iteman]

• Create 1.2 branch for the release if it does not exist
• Change the branch of the build status in README.md if the branch is newly created (1.2)
• Change README.md on the release branch. (1.2)
• Tag to the release on git with the command git tag -s v1.2.0 HEAD (1.2)
• Push changes to GitHub with the command git push upstream 1.2 and git push upstream --tags (1.2)
• Create a new draft release as PHPMentorsProxyURLRewriteBundle 1.2.0 (stable) (GitHub)
• Write the description of the release
  • The release date in UTC TZ=UTC date
• Publish the release
• Update wiki pages (Home)
• Update the version in README.md and composer.json from 1.2 to 1.3 if 1.2 branch is newly created (master)
• Push changes to GitHub with the command git push upstream master (master)
• Remove unnecessary releases in Packagist
• Remove unnecessary branches in GitHub
• Tweet the release