#530/#553: Fix python-environment and additional tag in release:trigger

[tomuben]

fixes #530: Nox task release:trigger also creates v* tag
fixes #553: Use Local copy of poetry installer in Github actions python-environment

Sample run of the updated GH Actions: exasol/integration-test-docker-environment#519

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?

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
96.9% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud