Fix BigQuery dataset schema name

[k1LoW]

<Dataset ID> to <Project ID>:<Dataset ID>

[codecov]

Codecov Report

Merging #101 into master will not change coverage.
The diff coverage is 100%.

@@           Coverage Diff           @@
##           master     #101   +/-   ##
=======================================
  Coverage   72.31%   72.31%           
=======================================
  Files          11       11           
  Lines        1983     1983           
=======================================
  Hits         1434     1434           
  Misses        414      414           
  Partials      135      135

Impacted Files	Coverage Δ
datasource/datasource.go	54.95% <100%> (ø)	⬆️

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