laravel 8 not supported

[shanbwp]

Problem 1
- Root composer.json requires guzzlehttp/guzzle ^7.2, found guzzlehttp/guzzle[7.2.0] but the package is fixed to 6.5.5 (lock file version) by a partial update and that version does not match. Make sure you list it as an argument for the update command.
Problem 2
- maxtee/blockchain dev-master requires illuminate/support 5.* -> found illuminate/support[v5.0.0, ..., 5.8.x-dev] but it conflicts with another require.
- Root composer.json requires maxtee/blockchain 9999999-dev -> satisfiable by maxtee/blockchain[].

Use the option --with-all-dependencies (-W) to allow upgrades, downgrades and removals for packages currently locked to specific versions.

Installation failed, reverting ./composer.json and ./composer.lock to their original content.