fix(deps): fix dependencies and update mjml example file to v4

[eseliger]

I moved gulp to a devDependency, as per gulp plugin guideline. I also added the keyword gulpplugin so it can be found in the gulp plugin search 🙂

The mjml test file was also in mjml v3 format, I migrated it to v4 as it is the version which is allowed in the semver range

Closes #36

[eseliger]

Hey together, I updated this pr to the latest master and this would still be nice to be merged, so this follows the gulp plugin guidelines!

[iRyusa]

Hi @eseliger Sorry about that one, can you just remove the package lock so we can merge it ? thanks !

[eseliger]

Hey @iRyusa the package-lock has only been modified and not added, and only relfects the changes to the package.json in this pr :)

[iRyusa]

Yep I know but we want to use yarn across our projects :D

On 4 Jul 2018, at 20:53, Erik Seliger notifications@github.com wrote:

Hey @iRyusa the package-lock has only been modified and not added, and only relfects the changes to the package.json in this pr :)

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[eseliger]

So shall I remove it completely? 🤔

[iRyusa]

Yep please !

On 4 Jul 2018, at 21:14, Erik Seliger notifications@github.com wrote:

So shall I remove it completely? 🤔

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[eseliger]

Done!

[eseliger]

hey, @iRyusa any updates how we can push this forward?

[iRyusa]

Forgot to merge it sorry 👍

[eseliger]

Thank you 🙂 let me know if you publish to npm!