Updated coverage report folder name

* Coverage report folder renamed
`terminus_client_coverage` -> `terminusdb_client_coverage`

Author: Pradhvan

.gitignore

@@ -20,7 +20,7 @@ woqlclient/*.egg-info/
 coverage.xml
 report.xml
 .coverage
-terminus_client_coverage/
+terminusdb_client_coverage/
 
 *.so
 *~

makefile

@@ -20,7 +20,7 @@ coverage:
 
 # Command to  generate a coverage report html
 coverage_html:
-	coverage html -d terminus_client_coverage
+	coverage html -d terminusdb_client_coverage
 
 interrogate:
 	interrogate -v -I -i -p -s terminusdb_client/woqlclient/woqlClient.py terminusdb_client/woqldataframe/woqlDataframe.py terminusdb_client/woqlquery/woql_query.py terminusdb_client/woqlquery/woql_library.py