Update pristine.yml

Author: jww3

.github/workflows/pristine.yml

@@ -22,6 +22,7 @@ jobs:
           wget -qO- https://cli.github.com/packages/githubcli-archive-keyring.gpg | tee /etc/apt/keyrings/githubcli-archive-keyring.gpg > /dev/null
           chmod go+r /etc/apt/keyrings/githubcli-archive-keyring.gpg
           echo "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/githubcli-archive-keyring.gpg] https://cli.github.com/packages stable main" | tee /etc/apt/sources.list.d/github-cli.list > /dev/null
+          add-apt-repository ppa:git-core/ppa
           apt update
           apt install gh -y        
           apt show gh