modify tox ini not to use deprecated libraries for unittests and add python 3.13 to tests

Author: szymonjas

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist = clean,docs,py37,py39
+envlist = clean,docs,py37,py39,313
 skipsdist = {env:TOXBUILD:false}
 
 [testenv:pep8]
@@ -28,8 +28,6 @@ setenv = SPLUNK_HOME=/opt/splunk
 allowlist_externals = make
 deps = pytest
        pytest-cov
-       xmlrunner
-       unittest-xml-reporting
        python-dotenv
 
 distdir = build