Use the compatible release clause in requirements.txt

requirements.txt

@@ -1,27 +1,27 @@
 # in alphabetical order
-astropy>=3.1
-celery>=4.3
-coverage>=4.5
-Django>=2.2
-django-allauth>=0.39
-django-compressor>=2.2
-django-extensions>=2.1
-django-filter>=2.1
-django-ipware>=2.1
-django-libsass>=0.7
-django-sendfile>=0.3
-django-settings-export>=1.2
-django-test-generator>=0.6
-django-vendor-files>=0.1
-django-widget-tweaks>=1.4
-djangorestframework>=3.9
-dj-database-url>=0.5.0
-drf-extensions>=0.4
-ipaddress>=1.0
-iso8601>=0.1
-jsonfield>=2.0
-Markdown>=3.1
-python-dotenv>=0.10
-queryparser_python3>=0.4
-rules>=2.0
-XlsxWriter>=1.1
+astropy~=3.1
+celery~=4.3
+coverage~=4.5
+Django~=2.2
+django-allauth~=0.39
+django-compressor~=2.2
+django-extensions~=2.1
+django-filter~=2.1
+django-ipware~=2.1
+django-libsass~=0.7
+django-sendfile~=0.3
+django-settings-export~=1.2
+django-test-generator~=0.6
+django-vendor-files~=0.1
+django-widget-tweaks~=1.4
+djangorestframework~=3.9
+dj-database-url~=0.5.0
+drf-extensions~=0.4
+ipaddress~=1.0
+iso8601~=0.1
+jsonfield~=2.0
+Markdown~=3.1
+python-dotenv~=0.10
+queryparser_python3~=0.4
+rules~=2.0
+XlsxWriter~=1.1