refactor(bigquery): update code samples of load table autodetect and …#100

HemangChothani wants to merge 3 commits intomasterMaxxleLLC/google-cloud-python:masterfrom

bigquery_update_load_table_autodetect_truncate_code_sampleMaxxleLLC/google-cloud-python:bigquery_update_load_table_autodetect_truncate_code_sampleCopy head branch name to clipboard