Update prismjs dependency version

[rogov-k]

Dear colleagues,

Today ngx-markdown has prismjs@^1.25.0 version. That version has vulnerability (see more issue 1, issue 2 and pull reques). I suggest to update prismjs to ^1.28.0 version. I tried to do it locally and it looks good at first glance.

[jfcere]

Hi @rogov-k,

Thank you for your contribution, your PR has been accepted and will be available in ngx-markdown v14 that will be released early next week alongside the update to Angular 14.

Please note that ngx-markdown version allows prism version 1.28.0 to be used as the dependency is set as ^1.25.0, so in the meanwhile just be sure to update your packages or force the update if you have a package-lock file.