CI: use latest deps for pandas-datareader, python-dateutil (pandas-dev#21204)

(cherry picked from commit dc02831)

Author: jreback

ci/travis-36.yaml

@@ -18,12 +18,10 @@ dependencies:
   - numexpr
   - numpy
   - openpyxl
-  - pandas-datareader
   - psycopg2
   - pyarrow
   - pymysql
   - pytables
-  - python-dateutil
   - python-snappy
   - python=3.6*
   - pytz
@@ -45,3 +43,5 @@ dependencies:
   - pip:
     - brotlipy
     - coverage
+    - pandas-datareader
+    - python-dateutil

pandas/tests/test_downstream.py

@@ -87,6 +87,7 @@ def test_pandas_gbq(df):
     pandas_gbq = import_module('pandas_gbq')  # noqa
 
 
+@pytest.mark.xfail(reason="0.7.0 pending")
 @tm.network
 def test_pandas_datareader():
 
@@ -95,6 +96,7 @@ def test_pandas_datareader():
         'F', 'quandl', '2017-01-01', '2017-02-01')
 
 
+@pytest.mark.xfail(reaason="downstream install issue")
 def test_geopandas():
 
     geopandas = import_module('geopandas')  # noqa