Update dependency google-api-core to v1.34.0

Author: renovate[bot]

requirements.txt

@@ -3,7 +3,7 @@ certifi==2020.6.20
 cffi==1.14.2
 chardet==3.0.4
 future==0.18.2
-google-api-core==1.22.1
+google-api-core==1.34.0
 google-auth==1.21.0
 google-cloud-bigquery==1.27.2
 google-cloud-core==1.4.1