Laravel 5.6 php版本冲突

Question

I am trying to install Laravel 5.6 in my new environment.

In my local environment, I have everything set up just fine. When I go to deploy to Elastic Beanstalk, I am running into a problem where the dependencies are forcing the server back into PHP v7.0.33.

How can the documentation of Laravel say that version 5.6 requires PHP 7.1.3 and up but the dependencies force me back to 7.0.33?

Here is the dependency list for PHP from Composer (I removed unrelated dependencies):

composer/ca-bundle  1.1.4       requires  php (^5.3.2 || ^7.0)
composer/composer   1.8.4       requires  php (^5.3.2 || ^7.0)
composer/semver     1.4.2       requires  php (^5.3.2 || ^7.0)
composer/spdx-licenses  1.5.0       requires  php (^5.3.2 || ^7.0)
composer/xdebug-handler 1.3.2       requires  php (^5.3.2 || ^7.0)
filp/whoops 2.3.1       requires  php (^5.5.9 || ^7.0)
fzaninotto/faker  v1.8.0      requires  php (^5.3.3 || ^7.0)
hamcrest/hamcrest-php  v2.0.0      requires  php (^5.3||^7.0)
phar-io/manifest   1.0.3       requires  php (^5.6 || ^7.0)
phar-io/version    2.0.1       requires  php (^5.6 || ^7.0)
phpdocumentor/reflection-docblock   4.3.0       requires  php (^7.0)
phpdocumentor/type-resolver    0.4.0       requires  php (^5.5 || ^7.0)
phpspec/prophecy    1.8.0       requires  php (^5.3|^7.0)
ramsey/uuid     3.8.0       requires  php (^5.4 || ^7.0)
sebastian/code-unit-reverse-lookup  1.0.1       requires  php (^5.6 || ^7.0)
seld/jsonlint  1.7.1       requires  php (^5.3 || ^7.0)
theseer/tokenizer    1.1.0       requires  php (^7.0)
tijsverkoyen/css-to-inline-styles  2.2.1       requires  php (^5.5 || ^7.0)
webmozart/assert   1.4.0       requires  php (^5.3.3 || ^7.0)

It seems to me that all these dependencies would not allow for an installation higher than the highest version of PHP 7.0. Am I reading this wrong?