metadata: need http timeout

[therealmitchconnors]

Client

metadata

Code

https://github.com/googleapis/google-cloud-go/blob/main/compute/metadata/metadata.go#L66

tcp dial timeout is set, but http timeout is not. If http server connects, but is slow to send response, client will hang indefinitely

Expected behavior

http timeout occurs

Actual behavior

client hangs indefinitely