build: use v2 of dependabolt (#1160)

Migrates to GitHub Actions v2.

Author: malept

.github/workflows/dependabolt.yml

@@ -10,6 +10,6 @@ jobs:
       if: github.event.ref_type == 'branch' && startsWith(github.event.ref, 'dependabot/')
       uses: actions/checkout@v1
     - name: Run dependabolt
-      uses: docker://malept/gha-dependabolt:1.1.0
+      uses: docker://malept/gha-dependabolt:2.0.0
       env:
         GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}