address composer plugin authorization change

in `test-integration`, we can see the following:

```
SEVERE: "[Bedrock Initializer]" " - Installing composer/installers (v1.12.0): Extracting archive"
Mar 20, 2022 3:04:11 PM wp2static-test.core invoke
SEVERE: "[Bedrock Initializer]" "For additional security you should declare the allow-plugins config with a list of packages names
that are allowed to run code. See https://getcomposer.org/allow-plugins"
Mar 20, 2022 3:04:11 PM wp2static-test.core invoke
SEVERE: "[Bedrock Initializer]" "You have until July 2022 to add the setting. Composer will then switch the default behavior to di
sallow all plugins."
```

more info on the change here: https://getcomposer.org/doc/06-config.md#allow-plugins

see if it will affect wp2static and adjust accordingly, explicitly allowing or denying before getting suprised by the behaviour change.