Create check of built packages

[Jannis-Mittenzwei]

closes #494

Checklist

Note: If any of the items in the checklist are not relevant to your PR, just check the box.

For any Pull Request

Is the following correct:

• the title of the Pull Request?
• the title of the corresponding issue?
• there are no other open Pull Requests for the same update/change?
• that the issue which this Pull Request fixes ("Fixes...") is mentioned?

When Changes Were Made

Did you:

• update the changelog?
• update the cookiecutter-template?
• update the implementation?
• check coverage and add tests: unit tests and, if relevant, integration tests?
• update the User Guide & other documentation?
• resolve any failing CI criteria (incl. Sonar quality gate)?

When Preparing a Release

Have you:

• thought about version number (major, minor, patch)?
• checked Exasol packages for updates and resolved open vulnerabilities, if easily possible?

[Shmuma]

@Jannis-Mittenzwei Test test_package_check is throwing ProcessError due to non-zero exit code from nox -s package:check.
This happens only in test environment and this task is returning the following stdout:

Building exasol-repo (0.1.0)
Building sdist
  - Building sdist
  - Built exasol_repo-0.1.0.tar.gz
Building wheel
  - Building wheel
  - Built exasol_repo-0.1.0-py3-none-any.whl
Checking 
/tmp/pytest-of-maxim.lapan/pytest-4/project_template_test0/repo/dist/exasol_repo
-0.1.0-py3-none-any.whl: FAILED
ERROR    `long_description` has syntax errors in markup and would not be        
         rendered on PyPI.                                                      
         line 11: Warning: Definition list ends without a blank line; unexpected
         unindent.                                                              
Checking 
/tmp/pytest-of-maxim.lapan/pytest-4/project_template_test0/repo/dist/exasol_repo
-0.1.0.tar.gz: FAILED
ERROR    `long_description` has syntax errors in markup and would not be        
         rendered on PyPI.                                                      
         line 11: Warning: Definition list ends without a blank line; unexpected
         unindent. 

I'm not very familiar with the logic, maybe you have more ideas what is wrong with the test environmet pytest creates.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
88.9% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud