Update default poetry version in example text and action

Author: ArBridgeman

.github/actions/python-environment/action.yml

@@ -11,7 +11,7 @@ inputs:
   poetry-version:
     description: 'Poetry version to use'
     required: true
-    default: "1.2.2"
+    default: "2.1.2"
 
 runs:
 

doc/github_actions/python_environment.rst

@@ -40,9 +40,9 @@ Example Usage
             uses: actions/checkout@v4
 
           - name: Setup Python & Poetry Environment
-            uses: exasol/python-toolbox/.github/actions/python-environment@0.9.0
+            uses: exasol/python-toolbox/.github/actions/python-environment@0.21.0
             with:
               python-version: 3.12
-              poetry-version: 1.2.2
+              poetry-version: 2.1.1
 
             ...