Fix build: align sdk_version with requirements.txt gradio pin

sdk_version 4.0.0 forced the build's pip install to request
gradio[oauth]==4.0.0 alongside requirements.txt's gradio==4.44.1
in the same command, causing a dependency resolution conflict
(BUILD_ERROR, exit code 1) once Docker layer caching was
invalidated by the prior README-only commit.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TjcgYCZjyAPxP1vq8X9VTn

README.md

@@ -4,7 +4,7 @@ emoji: "📣"
 colorFrom: "indigo"
 colorTo: "pink"
 sdk: "gradio"
-sdk_version: "4.0.0"
+sdk_version: "4.44.1"
 app_file: "app.py"
 pinned: false
 ---