diff --git a/dev-requirements.txt b/dev-requirements.txt
index 2e075ac..753d7fe 100644
--- a/dev-requirements.txt
+++ b/dev-requirements.txt
@@ -4,49 +4,117 @@
 #
 #    pip-compile dev-requirements.in
 #
-appdirs==1.4.3            # via virtualenv
-attrs==19.3.0             # via pytest
-backcall==0.1.0           # via ipython
-click==7.1.1              # via pip-tools
-coverage==5.0.3           # via pytest-cov
-decorator==4.4.2          # via ipython, traitlets
-distlib==0.3.0            # via virtualenv
-entrypoints==0.3          # via flake8
-filelock==3.0.12          # via tox, virtualenv
-flake8==3.7.9             # via -r dev-requirements.in
-freezegun==0.3.15         # via -r dev-requirements.in, pytest-freezegun
-importlib-metadata==1.5.0  # via pluggy, pytest, tox, virtualenv
-ipdb==0.13.2              # via -r dev-requirements.in
-ipython-genutils==0.2.0   # via traitlets
-ipython==7.13.0           # via -r dev-requirements.in, ipdb
-isort==4.3.21             # via -r dev-requirements.in
-jedi==0.16.0              # via ipython
-mccabe==0.6.1             # via flake8
-more-itertools==8.2.0     # via pytest
-packaging==20.3           # via pytest, tox
-parso==0.6.2              # via jedi
-pexpect==4.8.0            # via ipython
-pickleshare==0.7.5        # via ipython
-pip-tools==4.5.1          # via -r dev-requirements.in
-pluggy==0.13.1            # via pytest, tox
-prompt-toolkit==3.0.4     # via ipython
-ptyprocess==0.6.0         # via pexpect
-py==1.8.1                 # via pytest, tox
-pycodestyle==2.5.0        # via flake8
-pyflakes==2.1.1           # via flake8
-pygments==2.6.1           # via ipython
-pyparsing==2.4.6          # via packaging
-pytest-cov==2.8.1         # via -r dev-requirements.in
-pytest-freezegun==0.4.1   # via -r dev-requirements.in
-pytest==5.4.1             # via -r dev-requirements.in, pytest-cov, pytest-freezegun
-python-dateutil==2.8.1    # via -r dev-requirements.in, freezegun
-six==1.14.0               # via freezegun, packaging, pip-tools, python-dateutil, tox, traitlets, virtualenv
-toml==0.10.0              # via tox
-tox==3.14.5               # via -r dev-requirements.in
-traitlets==4.3.3          # via ipython
-virtualenv==20.0.10       # via -r dev-requirements.in, tox
-wcwidth==0.1.8            # via prompt-toolkit, pytest
-zipp==3.1.0               # via importlib-metadata
+attrs==19.3.0
+    # via pytest
+backcall==0.1.0
+    # via ipython
+click==7.1.1
+    # via pip-tools
+coverage==5.0.3
+    # via pytest-cov
+decorator==4.4.2
+    # via
+    #   ipython
+    #   traitlets
+distlib==0.3.9
+    # via virtualenv
+entrypoints==0.3
+    # via flake8
+filelock==3.16.1
+    # via
+    #   tox
+    #   virtualenv
+flake8==3.7.9
+    # via -r dev-requirements.in
+freezegun==0.3.15
+    # via
+    #   -r dev-requirements.in
+    #   pytest-freezegun
+ipdb==0.13.2
+    # via -r dev-requirements.in
+ipython==7.13.0
+    # via
+    #   -r dev-requirements.in
+    #   ipdb
+ipython-genutils==0.2.0
+    # via traitlets
+isort==4.3.21
+    # via -r dev-requirements.in
+jedi==0.16.0
+    # via ipython
+mccabe==0.6.1
+    # via flake8
+more-itertools==8.2.0
+    # via pytest
+packaging==20.3
+    # via
+    #   pytest
+    #   tox
+parso==0.6.2
+    # via jedi
+pexpect==4.8.0
+    # via ipython
+pickleshare==0.7.5
+    # via ipython
+pip-tools==4.5.1
+    # via -r dev-requirements.in
+platformdirs==4.3.6
+    # via virtualenv
+pluggy==0.13.1
+    # via
+    #   pytest
+    #   tox
+prompt-toolkit==3.0.4
+    # via ipython
+ptyprocess==0.6.0
+    # via pexpect
+py==1.8.1
+    # via
+    #   pytest
+    #   tox
+pycodestyle==2.5.0
+    # via flake8
+pyflakes==2.1.1
+    # via flake8
+pygments==2.6.1
+    # via ipython
+pyparsing==2.4.6
+    # via packaging
+pytest==5.4.1
+    # via
+    #   -r dev-requirements.in
+    #   pytest-cov
+    #   pytest-freezegun
+pytest-cov==2.8.1
+    # via -r dev-requirements.in
+pytest-freezegun==0.4.1
+    # via -r dev-requirements.in
+python-dateutil==2.8.1
+    # via
+    #   -r dev-requirements.in
+    #   freezegun
+six==1.14.0
+    # via
+    #   freezegun
+    #   packaging
+    #   pip-tools
+    #   python-dateutil
+    #   tox
+    #   traitlets
+toml==0.10.0
+    # via tox
+tox==3.14.5
+    # via -r dev-requirements.in
+traitlets==4.3.3
+    # via ipython
+virtualenv==20.26.6
+    # via
+    #   -r dev-requirements.in
+    #   tox
+wcwidth==0.1.8
+    # via
+    #   prompt-toolkit
+    #   pytest
 
 # The following packages are considered to be unsafe in a requirements file:
 # setuptools