[dependabot.yml] Add eng/tools, use increase-if-necessary, add eslint…

… group (#31479)

.github/dependabot.yml

@@ -1,10 +1,17 @@
 version: 2
 updates:
 - package-ecosystem: "npm"
-  directory: "/"
+  directories:
+  - "/"
+  - "/eng/tools/**"
   schedule:
     interval: "daily"
   groups:
     typespec:
       patterns:
       - "*typespec*"
+    eslint:
+      patterns:
+      - "*eslint*"
+  # Leave the constraint if the original constraint allows the new version, otherwise, bump the constraint.
+  versioning-strategy: increase-if-necessary