Fix version number of google-auth for Python 2.7
Fix version number of google-auth for Python 2.7

PiperOrigin-RevId: 310369571
Change-Id: Ic2677ac85e739b1839e05660a9533334d030f431

GoogleCloudPlatform/cloud-debug-python,GoogleCloudPlatform/cloud-debug-python,GoogleCloudPlatform/cloud-debug-python