add linter

[alacuku]

What type of PR is this?

Uncomment one (or more) /kind <> lines:

/kind bug

/kind cleanup

/kind documentation

/kind tests

/kind feature

Any specific area of the project related to this PR?

Uncomment one (or more) /area <> lines:

/area commands

/area pkg

/area events

What this PR does / why we need it:

This PR adds golanci-lint to the repository and applies it to the files.

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

[poiana]

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[poiana]

LGTM label has been added.

Git tree hash: dff785a151e7176644bfc840b327f8919f00a145

[poiana]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: alacuku, FedeDP

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Needs approval from an approver in each of these files: - ~~[OWNERS](https://github.com/falcosecurity/event-generator/blob/main/OWNERS)~~ [FedeDP,alacuku] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment