I got many issues like Package bsscommerce/configurable-product-matrix-view at version has a PHP requirement incompatible with your PHP version (7.2.14).
Using --ignore-platform-reqs, I could install it but after that it started to show error on Magento cloud while pushing code.
W: - bsscommerce/configurable-product-matrix-view 1.0.1 requires php ~5.5.0|~5.6.0|7.0.2|7.0.4|~7.0.6|~7.1.0 -> your PHP version (7.2.11) does not satisfy that requirement.
This error was due to the require PHP version in file composer.json
You only need delete this require element on file:
Afterward, install extension normally or via composer with the new composer.json file.