Remove mkiocccentry in test.yml workflow

This is because the mkiocccentry repo has offending markdown files.
Hopefully this resolves the workflow problem with find-invalid-json.sh
script and rule added to make test.

.github/workflows/test.yml

@@ -17,5 +17,7 @@ jobs:
       run: git clone https://github.com/ioccc-src/mkiocccentry
     - name: install jparse
       run: cd mkiocccentry && make all && cd jparse && sudo make all install
+    - name: remove mkiocccentry
+    - run: rm -fr mkiocccentry
     - name: make test
       run: make test