Restore failing when CVE scanner finds a vulnerability

[WyriHaximus]

During the migration to GitHub Actions in #160 this functionality
was mistakenly and overzealously removed. Since PHP 8 and
Alpine 3.13 are out and #166 has been filed, currently with a CVE
for musl in it, this check should have failed as it is our goal
to ship images without known CVE's in it. On my own PHP images
the CVE checking fails and as such I was surprised that #166
didn't have any failures. Up on checking the CI logs it showed
the musl CVE but the step didn't fail.

This commit restores the original functionality and will make the
CI once again fail when it finds a CVE in one of the images.

Usabilla PHP Docker Template

Reviewers: @usabilla/oss-docker

Type

Please specify the type of changes being proposed:

Q	A
Documentation?	no
Dockerfile change?	no
Build feature?	no
Apply CVE Patch?	no
Remove CVE Patch?	no

[rdohms]

Can we go back a step and explain:
A. the problem, B. Why this is the solution?

[WyriHaximus]

@rdohms Updated PR commit message and description

[agustingomes]

generally looks ok, but with the failing pipeline right now will be tricky to get this merged.

[WyriHaximus]

generally looks ok, but with the failing pipeline right now will be tricky to get this merged.

@agustingomes So it fails because it finds a CVE in the nginx 1.16 image for nginx ;)

[cvmiert]

generally looks ok, but with the failing pipeline right now will be tricky to get this merged.

@agustingomes So it fails because it finds a CVE in the nginx 1.16 image for nginx ;)

🤔 How will you be able to merge it in?

[WyriHaximus]

generally looks ok, but with the failing pipeline right now will be tricky to get this merged.

@agustingomes So it fails because it finds a CVE in the nginx 1.16 image for nginx ;)

How will you be able to merge it in?

That's the question! Can either fix that vurn in this PR, or fix it in a separate PR and then rebase