Adding tox support

Adds tox support for testing against multiple versions of python

.gitignore

@@ -61,3 +61,9 @@ tsfresh/notebooks/data/
 # dask
 dask-worker-space
 dask-worker-space/
+
+# python version files
+.python_version
+
+# tox log files
+.tox

setup.cfg

@@ -140,3 +140,23 @@ max-line-length = 120
 # This will be used when updating. Do not change!
 version = 3.2.3
 package = tsfresh
+
+[tox:tox]
+# Tox global conifguration options
+minversion = 4.0.0
+# Which python versions to test for
+envlist = py37, py38, py39, py310, py311
+# Don't throw an error if a specific version of python is not installed
+skip_missing_interpreters = True
+# Ensure that tox uses a virtual environment to build a source distribution
+isolated_build = True
+
+# Tox configuration options for each version of python
+[testenv]
+commands =
+    # display the python version that tests are being run on
+    python -V
+    # install package requirements before running tests
+    python -m pip install .[testing]
+    # run the tests
+    python -m pytest tests/