Bump pytest (and other dependencies) for Python 3.10

Signed-off-by: Hugo van Kemenade <hugovk@users.noreply.github.com>
diff --git a/test-requirements.txt b/test-requirements.txt
index 40161bb..d135792 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -1,7 +1,7 @@
-setuptools==54.1.1
-coverage==4.5.2
-flake8==3.6.0
+setuptools==58.2.0
+coverage==6.0.1
+flake8==4.0.1
 mock==1.0.1
-pytest==4.3.1
-pytest-cov==2.6.1
-pytest-timeout==1.3.3
+pytest==6.2.5
+pytest-cov==3.0.0
+pytest-timeout==2.0.1