Composer: Add branch alias for master

[ocean90]

See https://getcomposer.org/doc/articles/aliases.md for info about aliases in composer. This makes it easier to install dev-master while another package wants a specific version.

See Monolog as an example.

[ocean90]

Example use case: This project uses 6.1.5. Now I want to test new fixes/features so I'm going to try composer global require slevomat/coding-standard:"dev-master". But this fails:

❯ composer global require slevomat/coding-standard:"dev-master"
Changed current directory to /Users/Dominik/.composer
./composer.json has been updated
Loading composer repositories with package information
Updating dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - wearerequired/coding-standards dev-master requires slevomat/coding-standard 6.1.5 -> satisfiable by slevomat/coding-standard[6.1.5] but these conflict with your requirements or minimum-stability.
    - wearerequired/coding-standards dev-master requires slevomat/coding-standard 6.1.5 -> satisfiable by slevomat/coding-standard[6.1.5] but these conflict with your requirements or minimum-stability.
    - wearerequired/coding-standards dev-master requires slevomat/coding-standard 6.1.5 -> satisfiable by slevomat/coding-standard[6.1.5] but these conflict with your requirements or minimum-stability.
    - Installation request for wearerequired/coding-standards dev-master -> satisfiable by wearerequired/coding-standards[dev-master].

[kukulich]

composer global require slevomat/coding-standard:"dev-master as 6.1.99" should work I think.

[ocean90]

Yes, that works too. In my case I'd have to use "dev-master as 6.1.5" due to the strict version constrain.