fix: resolve yamllint errors in london-b host_vars and promtail config

- Remove trailing blank line in inventory/host_vars/london-b.yml
- Add missing document start marker to promtail config
- Fix indentation in promtail scrape_configs (indent list items under key)

ansible/inventory/host_vars/london-b.yml

@@ -20,4 +20,3 @@ common_ufw_allowed_ports:
   - {port: 6881, proto: tcp, comment: "BitTorrent"}
   - {port: 6881, proto: udp, comment: "BitTorrent"}
   - {port: 445, proto: tcp, comment: "Samba"}
-

ansible/services/promtail/config/london-b.yml

@@ -1,3 +1,4 @@
+---
 server:
   http_listen_port: 9080
   grpc_listen_port: 0
@@ -9,23 +10,23 @@ clients:
   - url: http://192.168.1.254:3100/loki/api/v1/push
 
 scrape_configs:
-- job_name: london-b
-  static_configs:
-  - targets:
-      - localhost
-    labels:
-      job: varlogs
-      instance: london-b
-      __path__: /var/log/*log
-  - targets:
-      - localhost
-    labels:
-      job: plex
-      instance: london-b
-      __path__: /var/lib/plexmediaserver/Library/Application Support/Plex Media Server/Logs/*log
-  - targets:
-      - localhost
-    labels:
-      job: jellyfin
-      instance: london-b
-      __path__: /var/log/jellyfin/*log
+  - job_name: london-b
+    static_configs:
+      - targets:
+          - localhost
+        labels:
+          job: varlogs
+          instance: london-b
+          __path__: /var/log/*log
+      - targets:
+          - localhost
+        labels:
+          job: plex
+          instance: london-b
+          __path__: /var/lib/plexmediaserver/Library/Application Support/Plex Media Server/Logs/*log
+      - targets:
+          - localhost
+        labels:
+          job: jellyfin
+          instance: london-b
+          __path__: /var/log/jellyfin/*log