Update symfony/process requirement to include version 7

[matrixes]

Hello, can we please update the symfony/process version requirements to "symfony/process": "^5.0|^6.0|^7.0" ?

Obviously, I'm not sure of any breaking changes that would affect this library, but we would like to use the library with a new Laravel v11 which installs "symfony/process v7" only

Thanks

[matrixes]

Would #93 be a healthy candidate for review?