build(deps): bump ruff from 0.15.20 to 0.15.21 in /ai/slackbot-mcp-client/rich-responses/mcp-apps (#121)

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

ai/slackbot-mcp-client/rich-responses/mcp-apps/requirements.txt

@@ -2,7 +2,7 @@ httpx2==2.5.0
 mcp==1.28.1
 mypy==2.2.0
 pytest==9.1.1
-ruff==0.15.20
+ruff==0.15.21
 slack_bolt==1.29.0
 slack_cli_hooks==0.3.0
 slack_sdk==3.43.0