chore: fix indentation in librarian.yaml (#16877)

Author: jskeet

librarian.yaml

@@ -71,12 +71,12 @@ libraries:
       name_pretty_override: Pandas Data Types for SQL systems (BigQuery, Spanner)
   - name: django-google-spanner
     version: 4.0.3
-	skip_generate: true
+    skip_generate: true
     python:
       library_type: INTEGRATION
   - name: gapic-generator
     version: 1.30.14
-	skip_generate: true
+    skip_generate: true
     python:
       library_type: CORE
       skip_readme_copy: true