diff --git a/poetry.lock b/poetry.lock
index ad8a445..97a48a9 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -664,7 +664,7 @@ description = "tox is a generic virtualenv management and test command line tool
 name = "tox"
 optional = false
 python-versions = "!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*,!=3.4.*,>=2.7"
-version = "3.19.0"
+version = "3.20.0"
 
 [package.dependencies]
 colorama = ">=0.4.1"
@@ -730,7 +730,8 @@ pre-commit = []
 travis-ci = []
 
 [metadata]
-content-hash = "671fad780d36ac7dc6dd10cd30638e640854b88b001b0adff8f0d5b4d3f73d1c"
+content-hash = "c91bd8889a0d9c543514cd6acc38edbd316633c2b5d4279d8af535df108316e1"
+lock-version = "1.0"
 python-versions = "^3.6"
 
 [metadata.files]
@@ -1047,8 +1048,8 @@ towncrier = [
     {file = "towncrier-19.2.0.tar.gz", hash = "sha256:48251a1ae66d2cf7e6fa5552016386831b3e12bb3b2d08eb70374508c17a8196"},
 ]
 tox = [
-    {file = "tox-3.19.0-py2.py3-none-any.whl", hash = "sha256:3d94b6921a0b6dc90fd8128df83741f30bb41ccd6cd52d131a6a6944ca8f16e6"},
-    {file = "tox-3.19.0.tar.gz", hash = "sha256:17e61a93afe5c49281fb969ab71f7a3f22d7586d1c56f9a74219910f356fe7d3"},
+    {file = "tox-3.20.0-py2.py3-none-any.whl", hash = "sha256:e6318f404aff16522ff5211c88cab82b39af121735a443674e4e2e65f4e4637b"},
+    {file = "tox-3.20.0.tar.gz", hash = "sha256:eb629ddc60e8542fd4a1956b2462e3b8771d49f1ff630cecceacaa0fbfb7605a"},
 ]
 urllib3 = [
     {file = "urllib3-1.24.2-py2.py3-none-any.whl", hash = "sha256:4c291ca23bbb55c76518905869ef34bdd5f0e46af7afe6861e8375643ffee1a0"},
diff --git a/pyproject.toml b/pyproject.toml
index b981cdc..752c41e 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -39,7 +39,7 @@ pytest-flake8 = "^1.0"
 responses = "^0.10.15"
 pytest-runner = "^5.2"
 towncrier = {version = "^19.2", optional = true}
-tox = "^3.19"
+tox = "^3.20"
 sphinx = {version = "^3.1", optional = true}
 sphinx_rtd_theme = {version = "^0.5.0", optional = true}
 pre-commit = {version = "^2.1", optional = true}