📝 PTB: Update poetry to 2.1.2

[ckunki]

PTB: Update poetry to 2.1.2

Acceptance criteria

• GitHub workflow files are updated
• Documentation is updated (if affected)

Rationale

Major python projects e.g. text-ai-extension have updated poetry to version >= 2, e.g. 2.0.1 in order to support cython for example. The SLC have been updated to 2.1.2

Files poetry.lock generated by poetry versions >= 2.0.0 are incompatible to older versions <= 1.0.0.

For other python projects, this either requires the developers to change poetry installation per-project or to update poetry for all python projects to a new version.

function install-poetry() {
    if [ "$1" = "ptb" ]; then
        pip uninstall poetry-plugin-shell
        pip install poetry==1.8.5 -U
    else
        pip install poetry==2.1.2 -U
        pip install poetry-plugin-shell # 1.0.1
    fi
}