Update loadgen version generator to 3.1

[nvzhihanj]

Still not fully fixed. Loadgen still throwing 3.0 as the version

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[nvzhihanj]

@pgmpablo157321 @arjunsuresh I still couldn't fully fix the issue after this PR. Can you advise what else I should change to make loadgen output 3.1 as the version?

[nv-ananjappa]

@pgmpablo157321 Could you contribute a fix to make the merge work?

[arjunsuresh]

@nvzhihanj It is working fine for me. I'm getting the below output in the log after these changes

arjunsuresh@Arjuns-MacBook-Pro ~ % cat test_results/Arjuns_MacBook_Pro.local-reference-cpu-tf-v2.13.0-default_config/resnet50/offline/performance/run_1/mlperf_log_detail.txt
:::MLLOG {"key": "loadgen_version", "value": "3.1 @ 1efeff1972", "time_ms": 0.021125, "namespace": "mlperf::logging", "event_type": "POINT_IN_TIME", "metadata": {"is_error": false, "is_warning": false, "file": "version.cc", "line_no": 54, "pid": 71353, "tid": 11698963673053299097}}