`sed` command fails on macOS due to BSD/GNU syntax differences

[sudoytang]

Hello,

I encountered an issue when running the plugin on macOS.
The setup process fails during the string replacement step because of how sed is invoked.

The current implementation uses sed -i without an extension argument, which works perfectly on Linux (GNU sed) but fails on macOS (BSD sed). BSD sed needs an extension argument after -i, or it will intepret the substitution string as the extension and the filename as the command, causing an error.

If it is possible I would like to submit a PR to fix this.
I propose to replace sed with perl -pi -e, this command does exactly what sed does but its behavior is consistent across OS.
Or if we are going to continue using sed, we may use sed -i.bak and then add a subsequent command to remove the generated .bak files.

Please let me know your preference and I will open a PR.