PHP

Root composer.json requires php ^7.2.5 but your php version (8.0.3) does not satisfy that require

It's becouse in your project in composer.json file you have:

"require": {
    "php": ">=7.3",
    .....
},
Try to update this requirement to:

"require": {
    "php": "^7.3|^8.0",
    .....
},

- root composer.json requires php ^7.1.3 but your php version (8.0.3) does not satisfy that requirement.

It's becouse in your project in composer.json file you have:

"require": {
    "php": ">=7.3",
    .....
},
Try to update this requirement to:

"require": {
    "php": "^7.3|^8.0",
    .....
},

- root composer.json requires php ^7.2 but your php version (8.0.1) does not satisfy that requirement.

Your project using php7.2 version and composer installed with 8.0.1.
Update your composer with php 7.2 instead 8.0.1. problem will solve.

root composer.json requires php ^7.3 but your php version (8.0.3) does not satisfy that requirement.

  "license": "MIT",
    "require": {
        "php": "^7.3|^8.0",

    },

root composer.json requires php ^7.1.3 but your php version (8.0.3) does not satisfy that requirement.

On Mac using Home Brew, you can switch php versions easily:
brew unlink php@8.0
brew link php@7.1

Or follow the upgrade path to get your app to support the newer php version

root composer.json requires php ^7.1.3 but your php version (8.0.1) does not satisfy that requirement.

for windows 
download php version you require
https://www.php.net/releases/index.php
then in variable environment of windows, edit PATH key, find php and update path to your new php version(after extract)

for ubuntu/linux
sudo apt-get install software-properties-common
sudo add-apt-repository ppa:ondrej/php
sudo apt-get update
sudo apt-get install php7.1

then if in future you want to switch between your php versions, 
sudo update-alternatives --config php