replace deprecated method grpc.DialContext in favour of grpc.NewClient

[tariq1890]

grpc.DialContext is deprecated and calls NewClient under the hood. We also remove the WithBlock call as the godoc of NewClient says that it is disregarded.

[nvvfedorov]

I ran unit tests, they fail with the error like:

--- FAIL: TestProcessPodMapper_WithD_Different_Format_Of_DeviceID (9.21s)
    --- FAIL: TestProcessPodMapper_WithD_Different_Format_Of_DeviceID/when_type_uid,_pod_device_id_b8ea3855-276c-c9cb-b366-c6fa655957c5_metric_device_id_b8ea3855-276c-c9cb-b366-c6fa655957c5_and_gpu_device_ (1.02s)
        kubernetes_test.go:322:
            	Error Trace:	/home/vfedorov/Documents/Github/fork/dcgm-exporter/pkg/dcgmexporter/kubernetes_test.go:322
            	Error:      	Received unexpected error:
            	            	failure getting pod resources; err: rpc error: code = Unavailable desc = name resolver error: produced zero addresses

[leharbhatt-okta]

I ran unit tests, they fail with the error like:

--- FAIL: TestProcessPodMapper_WithD_Different_Format_Of_DeviceID (9.21s)
    --- FAIL: TestProcessPodMapper_WithD_Different_Format_Of_DeviceID/when_type_uid,_pod_device_id_b8ea3855-276c-c9cb-b366-c6fa655957c5_metric_device_id_b8ea3855-276c-c9cb-b366-c6fa655957c5_and_gpu_device_ (1.02s)
        kubernetes_test.go:322:
            	Error Trace:	/home/vfedorov/Documents/Github/fork/dcgm-exporter/pkg/dcgmexporter/kubernetes_test.go:322
            	Error:      	Received unexpected error:
            	            	failure getting pod resources; err: rpc error: code = Unavailable desc = name resolver error: produced zero addresses

You might want to set the scheme as passthrough. When using Dial/DialContext the default scheme is passthrough whereas with NewClient, it is dns.