To create a minimalistic parser, nom is used to identify and replace
parameters given in the command field.
For clarity the `action` field for hooks was renamed to `command`.
In order to validate requests a field called `secret` has to be sent
containing a secret key which validates the request. A hook will be
executed only if the secret sent with the request matches the hook's
secret.
All dependencies were updated.
An example configuration file `config.yml` is added to show the
configuration options. Following locations are checked:
- `/etc/webhookey/config.yml`
- `<config_dir>/webhookey/config.yml`
- `./config.yml`
Whereas `<config_dir>` is depending on the platform:
- Linux: `$XDG_CONFIG_HOME` or `$HOME/.config`
- macOS: `$HOME/Library/Application Support`
- Windows: `{FOLDERID_RoamingAppData}`
Each hook's action is executed if all of the specified filters match.
