Fix prepare-release for Theia (#1626)

Author: tortmayr

.github/workflows/prepare-release.yml

@@ -65,7 +65,7 @@ on:
 
 jobs:
   release:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     steps:
       - name: Checkout release helper repo (@eclipse-glsp/glsp)
         uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
@@ -86,6 +86,12 @@ jobs:
         with:
           node-version: 20
 
+      - name: Set up Python
+        if: inputs.release_repo == 'glsp-theia-integration'
+        uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5.6.0
+        with:
+          python-version: '3.11'
+
       - name: Install Yarn
         run: npm install -g yarn