chore: move npm test to pre-push hook

[marcalexiei]

While rebasing #143 I noticed that now tests are run each time a commit is performed.

Someone (me 😅) could using commits as a backup of a work in progress. E.g.:

• make an incremental commit using --amend
• making a certain amount of commits and squash them together before push

In the current situation I would find myself unable to commit because some tests might be failing.
To be able to commit I have to add --no-verify flag to the commit command, which IMHO is not ideal.

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This PR basically move the npm test from pre-commit to pre-push hook.
I think is better to check that tests are working before push instead of every commit.

[elycruz]

Makes sense.