Add support to disable cancel button

[btmluiz]

The following options have been added:

• disableCancelButton

if disableCancelButton is true then the cancel button is not rendered, case disabeleCancelButton is false or undefined then the cancel button is rendered.

[jonatanklosko]

What is the use case for no cancel button? The user can still close the dialog by hitting on the overlay, so having a more accessible cancel button generally makes sense.

[btmluiz]

The use case is to use with allowClose option where the dialog will close only if the user confirms, making the confirmation mandatory.

An example is to show the user a secret_key where it will only be visable at that moment, in this case a cancel button is not necessary.

[jonatanklosko]

Ok! Let's rename the option to hideCancelButton, so it's not confused with disabled button state :)

[btmluiz]

@jonatanklosko renamed!

README.MD updated as well

[jonatanklosko]

Let's also add a default here:

material-ui-confirm/src/ConfirmProvider.js

Line 18 in 17d55d4

confirmationKeywordTextFieldProps: {},

and this is good to go :)

[jonatanklosko]

Published as v3.0.8 :)