Fix options in shebang line and updated rune access for PHP 7.4+

[serafdev]

First line requires -S if we want to pass a binary with options, tried in bash and fish:

❯ ./vcfconvert.sh -f csv -d "," -o contacts.csv ../Downloads/contacts.vcf
/usr/bin/env: ‘php -qC’: No such file or directory
/usr/bin/env: use -[v]S to pass options in shebang lines

The curly braces to access a rune is no longer supported:

❯ ./vcfconvert.sh -f csv -d "," -o contacts.csv ../Downloads/contacts.vcf
PHP Fatal error:  Array and string offset access syntax with curly braces is no longer supported in /home/seraf/vcfconvert/vcfconvert.sh on line 39