RequestCreator overriding explained

docs/about-get-started.rst

@@ -24,6 +24,17 @@ This library is initially built to support the current Soap Header v4, which is
 
 Legacy applications using already certified WSAP's can still be running on legacy Soap Header versions - most notably Soap Header 1 & 2. This library currently doesn't support those yet, but we plan to add that in the future.
 
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+Support for different versions of verbs
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+Amadeus periodically releases new versions of the verbs available on their web services.
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+On requesting access to the Amadeus web services, you'll receive a WSDL which contains messages in the lastest stable version Amadeus has released.
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+**There could be differences** in new versions of verbs: the request could be constructed differently (or have more options), you may get a slightly different response depending on the version you have received.
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+Therefore it's advised to test all options you will use and see if this library works for you! If it doesn't, you can inject a custom :code:`Amadeus\Client\RequestCreator\RequestCreatorInterface` which you can use to construct the messages as needed. This can be injected by passing a ``'requestCreator'`` in the client's params.
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 Install library in PHP project
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