chore(ci): disable dependabot and replace with Snyk (#3017)

We are not using dependabot to automatically upgrade our dependencies,
instead we will use Snyk to monitor our dependencies and alert us when
they need to be upgraded.

This should hopefully reduce the noise in our PR process.

.github/workflows/auto-merge.yml

@@ -1,14 +0,0 @@
-name: auto-merge
-
-on:
-  pull_request:
-
-jobs:
-  auto-merge:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v3
-      - uses: ahmadnassri/action-dependabot-auto-merge@v2
-        with:
-          # auto-merge rules are in /.github/auto-merge.yml
-          github-token: ${{ secrets.AUTO_MERGE_TOKEN }}

.github/workflows/check-pr-title.yml

@@ -9,4 +9,4 @@ jobs:
     steps:
     - uses: deepakputhraya/action-pr-title@master
       with:
-        regex: '^(feat|fix|breaking|build|chore|docs|style|refactor|test)\((kopiaui|cli|ui|repository|snapshots|server|providers|deps|deps-dev|site|ci|infra|general)\)!{0,1}: .*$'
+        regex: '^(\[Snyk\]|(feat|fix|breaking|build|chore|docs|style|refactor|test)\((kopiaui|cli|ui|repository|snapshots|server|providers|deps|deps-dev|site|ci|infra|general)\)!{0,1}:) .*$'