Exclude exe_running_docker_save in the "Update Package Repository" rule

[JPLachance]

What type of PR is this?
/kind bug
/kind rule-update

Any specific area of the project related to this PR?
/area rules

What this PR does / why we need it:
The "Update Package Repository" gets fired each time we launch a container.

{
    "output": "13:50:21.811741662: Notice Repository files get updated (user=root command=exe /var/lib/docker/overlay2/c8a17dac80b37bf1911335032d83ab0be5805fad1ddc02cfa6d591fd96de4927/diff file=/etc/yum.repos.d/CentOS-fasttrack.repo container_id=host image=<NA>) k8s.ns=<NA> k8s.pod=<NA> container=host k8s.ns=<NA> k8s.pod=<NA> container=host",
    "priority": "Notice",
    "output_fields": {
      "container.id": "host",
      "fd.name": "/etc/yum.repos.d/CentOS-fasttrack.repo",
      "proc.cmdline": "exe /var/lib/docker/overlay2/c8a17dac80b37bf1911335032d83ab0be5805fad1ddc02cfa6d591fd96de4927/diff",
      "user.name": "root",
      "evt.time": 1574949021811741700
    },
    "rule": "Update Package Repository"
  }

This event is surrounded by dozens like it.

Adding a simple and not exe_running_docker_save fixes the issue.

Which issue(s) this PR fixes:
I did not file an issue, here is the PR instead!

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

rules(Update Package Repository): fixed a false positive by excluding "exe_running_docker_save". 

[leodido]

This looks good to me!

Could you please reword the commit message (removing the ! at the start) ?

[poiana]

LGTM label has been added.

Git tree hash: 8f544daae218e3f8b0e11dc23727c7e7e679a742

[Kaizhe]

/lgtm

[poiana]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Kaizhe, leodido

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Needs approval from an approver in each of these files:

• rules/OWNERS [Kaizhe,leodido]

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[leodido]

/milestone 0.19.0