add versions to requirements.txt

official/requirements.txt

@@ -2,10 +2,10 @@ google-api-python-client>=1.6.7
 google-cloud-bigquery>=0.31.0
 kaggle>=1.3.9
 mlperf_compliance==0.0.10
-numpy
+numpy>=1.15.4
 oauth2client>=4.1.2
-pandas
+pandas>=0.22.0
 psutil>=5.4.3
 py-cpuinfo>=3.3.0
-scipy
+scipy>=0.19.1
 typing