Declare pip dependency for cli extras

The `pipdeptree` package includes references
to `pip` but does not explicitly require it.
To ensure `pip` is installed in the environment,
declare it as a dependency.

pyproject.toml

@@ -83,6 +83,8 @@ botocore = {version = ">=1.28", optional = true}
 snowflake-connector-python = {version = ">=3.5.0", optional = true}
 cron-descriptor = {version = ">=1.2.32", optional = true}
 pipdeptree = {version = ">=2.9.0,<2.10", optional = true}
+# pip is used by pipdeptree but not listed in its dependencies
+pip = {version = ">=24.0.0", optional = true}
 pyathena = {version = ">=2.9.6", optional = true}
 weaviate-client = {version = ">=3.22", optional = true}
 adlfs = {version = ">=2024.7.0", optional = true}
@@ -126,7 +128,7 @@ az = ["adlfs"]
 sftp = ["paramiko"]
 snowflake = ["snowflake-connector-python"]
 motherduck = ["duckdb", "pyarrow"]
-cli = ["pipdeptree", "cron-descriptor"]
+cli = ["pipdeptree", "cron-descriptor", "pip"]
 athena = ["pyathena", "pyarrow", "s3fs", "botocore"]
 weaviate = ["weaviate-client"]
 mssql = ["pyodbc"]