I faced the same problem. It took me two days to get this thing working.
I am writing about the whole setup. please refer to step 2 for the answer to the question. FYI my OS is windows 10
Step 1:
Firstly, I faced problems installing gcloud and this is what i did.
The script(.\google-cloud-sdk\install.bat) which is supposed to add gcloud to the path was not working due to permission issues.
I had to add the path manually in two places
1) In the system variables, to the "PATH" variable i added the path to the gcloud bin which should look like - C:\Users\774610\google-cloud-sdk\bin - in my case
2) Additionally gcloud needs python so to the "PATHEXT" variable i appended ".PY" at the end.
After Performing these tasks gcloud started working.
Step 2:
Even though gcloud is working, maven is not able to connect to cloud storage and the error was "401 Anonymous caller does not have storage.objects.list access to bucket"
I was pretty sure i did login to my account and selected the correct project. I also tried adding environment variable as shown in this documentation "https://cloud.google.com/docs/authentication/getting-started"
Nothing seemed to be working even though all the credentials were perfectly setup.
while going through the gcloud documentation I came across this command - "gcloud auth application-default login" which was exactly what i needed.
Refer here for difference between gcloud auth login and gcloud auth application default login
In short what this command does is it obtains your credentials via a web flow and stores them in 'the well-known location for Application Default Credentials' and any code/SDK you run will be able to find the credentials automatically
After this, maven was successfully able to connect to google storage and do its stuff.
Hope this helps, thanks