Add a project script setup for db2json

pyproject.toml:
Add a script setup for dbj2son pointing to `repo_management.cli:db2json`.
This can be used via `poetry run db2json`.

pyproject.toml

@@ -25,6 +25,9 @@ black = "^20.8b1"
 coverage = "^5.5"
 mock = "^4.0.3"
 
+[tool.poetry.scripts]
+db2json = "repo_management.cli:db2json"
+
 [tool.black]
 line-length = 120
 exclude = '''