Using python 3.11 by pyenv

Bug: 394025850
Change-Id: Ia7c131ed825a206ec0a399211786ee765bc2f2a7
Test: kokoro
diff --git a/build/debian/kokoro/gcp_ubuntu_docker/x86_64/build.sh b/build/debian/kokoro/gcp_ubuntu_docker/x86_64/build.sh
index a935591..0655046 100644
--- a/build/debian/kokoro/gcp_ubuntu_docker/x86_64/build.sh
+++ b/build/debian/kokoro/gcp_ubuntu_docker/x86_64/build.sh
@@ -2,6 +2,13 @@
 
 set -e
 
+git clone https://github.com/pyenv/pyenv.git ~/.pyenv
+export PYENV_ROOT="$HOME/.pyenv"
+export PATH="$PYENV_ROOT/bin:$PATH"
+pyenv install 3.11
+pyenv global 3.11
+python --version
+
 cd "${KOKORO_ARTIFACTS_DIR}/git/avf/build/debian/"
 sudo losetup -D
 grep vmx /proc/cpuinfo || true