Add .graphql to source_extensions and remove .md

- Add .graphql extension to source_extensions for GraphQL schema change detection
- Remove .md extension as it only includes documentation files that don't affect builds

Author: Taniya Mathur

publish.py

@@ -1983,10 +1983,10 @@ def get_source_files_checksum(self, directory):
             ".yml",
             ".json",
             ".txt",
-            ".md",
             ".toml",
             ".cfg",
             ".ini",
+            ".graphql",
         }
         exclude_dirs = {
             "__pycache__",