env: downgrade zipp to restore compatibility with python3.5

Pipfile

@@ -8,3 +8,7 @@ acpi-backlight = {editable = true, path = "."}
 
 [dev-packages]
 pytest = "*"
+
+# zipp v2.0.0 dropped support for python3.5
+# https://github.com/jaraco/zipp/commit/05a3c52b4d41690e0471a2e283cffb500dc0329a
+zipp = "<2"

Pipfile.lock

@@ -1,7 +1,7 @@
 {
     "_meta": {
         "hash": {
-            "sha256": "2655328f1e9ed14b06d0846810d70db664b6f25271199e6c9a2e9dd222e28581"
+            "sha256": "b10e6c4a46734a8aacff32bb37fa2b8c8acbd45340fb17b5e9b446512dfe0b70"
         },
         "pipfile-spec": 6,
         "requires": {},
@@ -94,10 +94,11 @@
         },
         "zipp": {
             "hashes": [
-                "sha256:aa36550ff0c0b7ef7fa639055d797116ee891440eac1a56f378e2d3179e0320b",
+                "sha256:c70410551488251b0fee67b460fb9a536af8d6f9f008ad10ac51f615b6a521b1",
-                "sha256:c599e4d75c98f6798c509911d08a22e6c021d074469042177c8c86fb92eefd96"
+                "sha256:e0d9e63797e483a30d27e09fffd308c59a700d365ec34e93cc100844168bf921"
             ],
-            "version": "==3.1.0"
+            "index": "pypi",
+            "version": "==1.2.0"
         }
     }
 }