Specify plyr dependency version

[core01]

Hi, it is unsafe to use plyr from the develop branch, let's use the latest version of the plyr, what do you think about it?

[gavinwilliams]

Would be great if someone accepted this PR, this component no longer works and NPM complains that package.json is missing on the develop branch.

For anyone having issues, I've done the following to work around it.

npm shrinkwrap

Find vue-plyr in npm-shrinkwrap.json

Change the plyr dependency to 3.6.10

Old

      "requires": {
        "plyr": "plyr@github:sampotts/plyr#master",
        "vue": "^2.6.12"
      },

New

      "requires": {
        "plyr": "3.6.10",
        "vue": "^2.6.12"
      },

Save and run npm install