Alpine oldest: php5-openssl (#3482)
Alpine oldest: php5-openssl (#3482)

alpine:3.13 require php5-openssl for some https features.

Otherwise, fail on e.g. the extension page:

```
file_get_contents(): php Unable to find the wrapper "https" - did you
forget to enable it when you configured PHP? in
/var/www/FreshRSS/app/Controllers/extensionController.php on line 45

PHP Warning:
file_get_contents(https://raw.githubusercontent.com/FreshRSS/Extensions/master/extensions.json):
failed to open stream: No such file or directory in
/var/www/FreshRSS/app/Controllers/extensionController.php on line 45

[error] --- Could not fetch available extension from GitHub
```

Does not seem required for newer Alpine versions using PHP7 / PHP8
FreshRSS/FreshRSS,aledeg/FreshRSS,Alkarex/FreshRSS,Alkarex/FreshRSS,FreshRSS/FreshRSS,aledeg/FreshRSS,Alkarex/FreshRSS,FreshRSS/FreshRSS,Alkarex/FreshRSS,FreshRSS/FreshRSS,aledeg/FreshRSS,aledeg/FreshRSS