GIT - Set dependabot checks to monthly

Change-Id: If4db71c0d7b68bc03ba302a01e6cf779a32e4c2b
Signed-off-by: Galantsev, Dmitrii <dmitrii.galantsev@amd.com>

.github/dependabot.yml

@@ -9,7 +9,7 @@ updates:
     directory: "/docs/sphinx" # Location of package manifests
     open-pull-requests-limit: 10
     schedule:
-      interval: "daily"
+      interval: "monthly"
     target-branch: "master"
     labels:
       - "documentation"