ci: reduce frequency of auto updates (#328)

Reduce frequency of auto-update jobs:
* Update third-party package metadata
* Bump dependency version
Both are now monthly rather than weekly.

.github/workflows/deps.yml

@@ -3,7 +3,7 @@ permissions:
   contents: read
 on:
   schedule:
-    - cron: "22 5 * * 1"
+    - cron: "22 5 2 * *"
 jobs:
   upgrade:
     runs-on: ubuntu-latest

.github/workflows/metadata.yml

@@ -3,7 +3,7 @@ permissions:
   contents: read
 on:
   schedule:
-    - cron: "24 5 * * 0"
+    - cron: "24 5 1 * *"
 jobs:
   update:
     runs-on: ubuntu-latest