Improve definitions' sort
Improve definitions' sort

With this change the stable versions, like 1.0.0 are displayed after the
unstable versions, like 1.0.0beta2, 1.0.0-rc1.

The "~" was chosen because it is one of the lastest chars in the ASCII
table.

Example:
```
 7.0.0alpha1
 7.0.0alpha2
 7.0.0beta1
 7.0.0beta2
 7.0.0beta3
 7.0.0
 7.0.1
 7.1.0-rc1
 7.1.0
 7.1.1
```

gerardroche/php-build,hirak/php-build,rogeriopradoj/php-build,hnw/php-build,circleci/php-build,php-build/php-build,michael-berlin/php-build,0livier/php-build