Ignore unapproved actions/setup-python versions in Dependabot (#70)

actions/setup-python v6.3.0 is not on the CrowdStrike org's GitHub Actions allowlist, so Dependabot PRs for it can't run CI (no checks fire). Add an ignore rule matching the pattern already used for actions/checkout and actions/setup-node.

Author: mraible

.github/dependabot.yml

@@ -12,3 +12,5 @@ updates:
         versions: [">=6.0.3"]
       - dependency-name: "actions/setup-node"
         versions: [">=6.3.0"]
+      - dependency-name: "actions/setup-python"
+        versions: [">=6.3.0"]