feat: exclude dependabot from dev and prod steps

Since dependabot does not have access to the secrets in the github app token generation step, this step fails in the PRs with sha updates, so we are excluding dependabot from running gatekeeper jobs.

Author: Vlad Rusu

.github/workflows/reusable-gatekeeper.yml

@@ -130,6 +130,7 @@ jobs:
           echo "matrix=${CLUSTER_JSON}" >> $GITHUB_OUTPUT
 
   gatekeeper-enforce-dev:
+    if: github.actor != 'dependabot[bot]'
     needs:
       - validate-caller-repos
       - enumerate-dev-clusters
@@ -184,6 +185,7 @@ jobs:
             "${{ inputs.gator-version }}"
 
   gatekeeper-enforce-prod:
+    if: github.actor != 'dependabot[bot]'
     needs:
       - validate-caller-repos
       - enumerate-prod-clusters