Update dependency gunicorn to v20.1.0

requirements.txt

@@ -98,10 +98,8 @@ djangorestframework==3.12.2 \
     --hash=sha256:0209bafcb7b5010fdfec784034f059d512256424de2a0f084cb82b096d6dd6a7 \
     --hash=sha256:0898182b4737a7b584a2c73735d89816343369f259fea932d90dc78e35d8ac33
     # via -r requirements.in
-gunicorn==20.0.4 \
-    --hash=sha256:1904bb2b8a43658807108d59c3f3d56c2b6121a701161de0ddf9ad140073c626 \
-    --hash=sha256:cd4a810dd51bf497552cf3f863b575dabd73d6ad6a91075b65936b151cbf4f9c
-    # via -r requirements.in
+gunicorn==20.1.0 \
+    --hash=sha256:e0a968b5ba15f8a328fdfd7ab1fcb5af4470c28aaf7e55df02a99bc13138e6e8
 idna==2.10 \
     --hash=sha256:b307872f855b18632ce0c21c5e45be78c0ea7ae4c15c828c20788b26921eb3f6 \
     --hash=sha256:b97d804b1e9b523befed77c48dacec60e6dcb0b5391d57af6a65a312a90648c0