Update symfony/css-selector requirement from ^3.4|^4.4|^5.4|^6.0 to ^3.4|^4.4|^5.4|^6.0|^7.0

Update symfony/css-selector requirement from ^3.4|^4.4|^5.4|^6.0 to ^3.4|^4.4|^5.4|^6.0|^7.0 #27