github: Use Dependabot to keep Actions updated (#518)

diff --git a/.github/dependabot.yml b/.github/dependabot.yml
index 083d5d9..55568ef 100644
--- a/.github/dependabot.yml
+++ b/.github/dependabot.yml
@@ -11,9 +11,6 @@
       interval: weekly
     labels:
       - dependencies
-    # only update HashiCorp actions, external actions managed by TSCCR
-    allow:
-      - dependency-name: hashicorp/*
     groups:
       github-actions-breaking:
         update-types: