Upgrade edx-when to 0.7.0 to drop course date signal handling

requirements/edx/base.txt

@@ -121,7 +121,7 @@ edx-sga==0.10.0
 edx-submissions==3.0.3
 edx-tincan-py35==0.0.5    # via edx-enterprise
 edx-user-state-client==1.1.2
-edx-when==0.6.0
+edx-when==0.7.0
 edxval==1.2.3
 elasticsearch==1.9.0      # via edx-search
 enum34==1.1.6             # via edxval

requirements/edx/development.txt

@@ -134,7 +134,7 @@ edx-sphinx-theme==1.5.0
 edx-submissions==3.0.3
 edx-tincan-py35==0.0.5
 edx-user-state-client==1.1.2
-edx-when==0.6.0
+edx-when==0.7.0
 edxval==1.2.3
 elasticsearch==1.9.0
 entrypoints==0.3

requirements/edx/testing.txt

@@ -129,7 +129,7 @@ edx-sga==0.10.0
 edx-submissions==3.0.3
 edx-tincan-py35==0.0.5
 edx-user-state-client==1.1.2
-edx-when==0.6.0
+edx-when==0.7.0
 edxval==1.2.3
 elasticsearch==1.9.0
 entrypoints==0.3          # via flake8