update to Django 2.1

Pipfile

@@ -7,7 +7,7 @@ verify_ssl = true
 
 [packages]
 ndh = ">=3.9.0"
-django = "<2.1"
+django = "<2.2"
 django-filter = "*"
 "django-tables2" = "*"
 requests = "*"

Pipfile.lock

 {
     "_meta": {
         "hash": {
-            "sha256": "7bb5dfc873706f38f9b6c684ca7ea918b1629265fd3b57937dfc599366771ff8"
+            "sha256": "5be37f56fd74d155101f4acba6c915a939da8504055024743fd47e77a1c3dfce"
         },
         "pipfile-spec": 6,
         "requires": {
@@ -32,11 +32,11 @@
         },
         "django": {
             "hashes": [
-                "sha256:0c5b65847d00845ee404bbc0b4a85686f15eb3001ffddda3db4e9baa265bf136",
-                "sha256:68aeea369a8130259354b6ba1fa9babe0c5ee6bced505dea4afcd00f765ae38b"
+                "sha256:04f2e423f2e60943c02bd2959174b844f7d1bcd19eabb7f8e4282999958021fd",
+                "sha256:e1cc1cd6b658aa4e052f5f2b148bfda08091d7c3558529708342e37e4e33f72c"
             ],
             "index": "pypi",
-            "version": "==2.0.8"
+            "version": "==2.1.1"
         },
         "django-autoslug-iplweb": {
             "hashes": [