GHA: add the LibreOffice PPA without Launchpad's broken key API

add-apt-repository fails with GPGKeyTemporarilyNotFoundError since
Launchpad's getSigningKeyData endpoint is down, blocking every run.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: chris-adam

.github/workflows/python-package.yml

@@ -30,7 +30,12 @@ jobs:
       - name: Setup Env
         run: |
           mkdir -p -m 777 /tmp/appy/
-          sudo add-apt-repository ppa:libreoffice/ppa -y
+          # add-apt-repository is unusable while Launchpad's key API answers
+          # GPGKeyTemporarilyNotFoundError, so add the PPA without it
+          curl -fsSL "https://keyserver.ubuntu.com/pks/lookup?op=get&search=0xCDDE43BA4DE3F09D7CE7016673AEE920AD55F5A0" \
+            | sudo tee /etc/apt/trusted.gpg.d/libreoffice-ppa.asc > /dev/null
+          echo "deb https://ppa.launchpadcontent.net/libreoffice/ppa/ubuntu $(lsb_release -cs) main" \
+            | sudo tee /etc/apt/sources.list.d/libreoffice-ppa.list
           sudo apt update -qq -y
           sudo apt-get install -qq -y libreoffice libreoffice-script-provider-python libjpeg62 libjpeg62-dev libbz2-dev
           /usr/bin/python3 -m pip install -q --target uno-libs persistent