publish phars as github release assets

[glensc]

instead of commiting the binary blobs to git repository, upload them to each release:

• https://github.com/pear/pearweb_phars/releases/tag/v1.10.10

you can automate the .phar upload with travis. signature is a bit more difficult, you probably need to use secret variable to encrypt gpg key.

• https://docs.travis-ci.com/user/deployment/releases

some examples:

• https://github.com/eventum/eventum/blob/v3.5.6/.travis.yml#L30-L54
• https://github.com/eventum/scm/blob/v3.1.3/.travis.yml#L37-L50
• https://github.com/glensc/nagios-plugin-check_raid/blob/4.0.8/.travis.yml#L23-L59

[nikic]

One reason why this would be useful is that download of individual files from a repository is subject to pretty aggressive rate limiting, so if you have multiple CI jobs running in parallel, trying to download these phars from GitHub, the download is likely to fail.