Fix greek phone numbers

[sebdesign]

This PR fixes the greek phone numbers, because the existing phone numbers are not valid according to libphonenumber.

I've used the data from Wikipedia and the regular expressions from giggsey/libphonenumber-for-php to generate valid greek numbers.

The tests are not extensive but I ran them 10000 times using phpunit test/Faker/Provider/el_GR/PhoneNumberTest.php --repeat 10000 and they all pass.

[pimjansen]

Can we add some PHPDoc in the new methods? I know its not there everywhere but it will help us future wise a lot

[sebdesign]

@pimjansen I've added return types as well as docblocks with descriptions and examples.

[pimjansen]

@sebdesign, you introduced a breaking change by setting up the return types.

[sebdesign]

Ah, you're right, I removed them now.

[sebdesign]

@pimjansen BC check is still squawking because i changed some methods from static to non-static.

I suppose this is not an issue, because the the provider methods would never be called directly, but only via Generator::format(), right?

[pimjansen]

Its not a final close so you change the interface of the actual and therefor it is breaking

[sebdesign]

If I make the methods static I won't be able to use $this->generator->parse(). I'll have to find a workaround to replace {{formatter}} with actual values. Is that ok with you?

[bram-pkg]

You can use string interpolation.

[bram-pkg]

Looks good to me.

[pimjansen]

Thanks!