add missing dep: python-dotenv

Pipfile

@@ -27,6 +27,7 @@ wrapt = "==1.12.1"
 stripe = "*"
 matplotlib = "*"
 requests = "*"
+python-dotenv = "*"
 
 [dev-packages]
 

Pipfile.lock

@@ -1,7 +1,7 @@
 {
     "_meta": {
         "hash": {
-            "sha256": "30ae24715ab8f45ada9d367e0a7ef6e1b1a6a5f88cb0dd6bb6c3cd3b385f817f"
+            "sha256": "4f61804f9405ff8f66e41739aeac24a2577f7b64f7d08b93459b568528c4f494"
         },
         "pipfile-spec": 6,
         "requires": {
@@ -304,6 +304,14 @@
             ],
             "version": "==2.8.1"
         },
+        "python-dotenv": {
+            "hashes": [
+                "sha256:25c0ff1a3e12f4bde8d592cc254ab075cfe734fc5dd989036716fd17ee7e5ec7",
+                "sha256:3b9909bc96b0edc6b01586e1eed05e71174ef4e04c71da5786370cebea53ad74"
+            ],
+            "index": "pypi",
+            "version": "==0.13.0"
+        },
         "requests": {
             "hashes": [
                 "sha256:43999036bfa82904b6af1d99e4882b560e5e2c68e5c4b0aa03b655f3d7d73fee",