Fix misaligned indent for rack_attack

For #2244 (closed)

When enabling rack_attack we see this:

        rack_attack:
          git_basic_auth:
+         bantime: 3600
+         enabled: true
+         findtime: 180
+         ip_whitelist:
+         - 127.0.0.1
+         maxretry: 30

Fixes the indention issue so the values are uder git_basic_auth