requirements: fix versions

requirements.txt

@@ -1,26 +1,26 @@
 Django<1.11.0
 git+https://github.com/parksandwildlife/dpaw-utils.git@0.3a13#egg=dpaw-utils
 git+https://github.com/django-oscar/django-oscar.git@feature/django-110#egg=django-oscar
-social-auth-app-django>=0.1.0
-coverage>=4.0.3
-coveralls>=1.1
+social-auth-app-django==0.1.0
+coverage==4.3.1
+coveralls==1.1
 reportlab==3.3.0
-django_bootstrap3>=6.2.2
+django_bootstrap3==7.1.0
 django-braces>=1.8.1
 django-datatables-view==1.13.0
 django-reversion==1.10.1
 git+https://github.com/scottp-dpaw/django-preserialize.git#egg=django-preserialize
 django-countries==3.4.1
 django-cron==0.4.6
-django-dynamic-fixture>=1.9.0
+django-dynamic-fixture==1.9.1
 openpyxl==2.3.5
 datapackage==0.8.1
 jsontableschema==0.6.5
 python-dateutil==2.5.3
 py4j==0.10.2.1
 djangorestframework==3.4.0
-djangorestframework-gis
+djangorestframework-gis==0.11
 pycountry==1.20
 six>=1.10.0
-django-ical>=1.4
-django-taggit
+django-ical==1.4
+django-taggit==0.21.3