fix(ci): remove Python 3.9 case from run_single_test.sh

This removes the case for Python 3.9 in the unit test section, as we no longer run tests for this version.

Author: chalmerlowe

ci/run_single_test.sh

@@ -70,10 +70,7 @@ case ${TEST_TYPE} in
         ;;
     unit)
         case ${PY_VERSION} in
-        "3.9")
-            nox -s unit-3.9
-            retval=$?
-            ;;
+
         "3.10")
             nox -s unit-3.10
             retval=$?