Fix environment variable setting

.github/workflows/generate_readme.yaml

@@ -32,7 +32,7 @@ jobs:
               var_name="$(echo "${file^^}" | tr "./" "_")"
               # Export file contents to an environment variable named from the path, e.g.:
               # 'section/test_file.md' would be 'SECTION_TEST_FILE_MD'
-              export "${!var_name}"= <"$file"
+              export "${!var_name}"="$(<"$file")"
               envsubst < "${!var_name}"  # Substitute environment variables into each section (not other sections)
             fi 
         done