More compatible filter.ml

Add post filtering of test output to fix OCaml 5.2

Remove unneeded non-POSIX-compilent grep invocation in the tests (#1)

Test older OCaml

Filter test output to exactly what we want

Update dune files

Update license field

Rudimentary filtering ability

Rename type error test directory

Clean up testing

Update test output

Simplify into one mapper

Add basic github action

Generate dummy code to type check arguments in non-logging case

Clean up