env: downgrade importlib-metadata to restore compatibility with python3.4

Pipfile

@@ -10,6 +10,9 @@ free-disk = {editable = true, path = "."}
 # v2.3.0 dropped python3.4 support
 # https://github.com/PyCQA/astroid/commit/4a4b7faf9de8437f2b96bc7285802fd1230b7a9a
 astroid = "<2.3.0"
+# v1.2.0 dropped python3.4. support
+# https://gitlab.com/python-devs/importlib_metadata/commit/cf58e1a6515adc4ad6f84cce5e89cd5ef830b317
+importlib-metadata = "<1.2.0"
 # v8.0.0 dropped python3.4 support
 more-itertools = "<8"
 # v2.4.0 dropped python3.4 support

Pipfile.lock

@@ -1,7 +1,7 @@
 {
     "_meta": {
         "hash": {
-            "sha256": "512e7f5f7622fafcb1ece27ac220fd6643e9bebcdb2c4d6afb8fd62a534aa9e7"
+            "sha256": "bfa316df77f1f413347cb7086967e40787b2b7ad3d3e086a7f7df2216f462e22"
         },
         "pipfile-spec": 6,
         "requires": {
@@ -46,11 +46,11 @@
         },
         "importlib-metadata": {
             "hashes": [
-                "sha256:073a852570f92da5f744a3472af1b61e28e9f78ccf0c9117658dc32b15de7b45",
-                "sha256:d95141fbfa7ef2ec65cfd945e2af7e5a6ddbd7c8d9a25e66ff3be8e3daf9f60f"
+                "sha256:7a99fb4084ffe6dae374961ba7a6521b79c1d07c658ab3a28aa264ee1d1b14e3",
+                "sha256:7c7f8ac40673f507f349bef2eed21a0e5f01ddf5b2a7356a6c65eb2099b53764"
             ],
-            "markers": "python_version < '3.8'",
-            "version": "==1.3.0"
+            "index": "pypi",
+            "version": "==1.1.3"
         },
         "isort": {
             "hashes": [