missing config argument in installation test file

[sschmidt23]

The installation instructions ask the user to run
python scripts/processFilters.py tests/parametersTest.cfg as part of the install checks. This currently results in a KeyError exception because sed_fmt is missing from the test config file. It looks like missing keywords used to not result in a KeyError and would have default values assigned, I guess configparser must have updated how they handle missing keywords at some point in the last 8 years.

Simple solution for now is to add sed_fmt: sed to the config so that the tests run again. Eventually we may want to look more into configparser and see if we can turn off the KeyError for missing args or see if there is some updated way of handling default values.