Add pre-commit to list of deps branches (#969)

Adds branches created by pre-commit when updating dependencies to the
list of branches with 'dependencies' label.

Author: lucacome

.github/labeler.yml

@@ -18,5 +18,5 @@ documentation:
   - changed-files: '**/*.md'
 
 dependencies:
-  - head-branch: ['^deps/', '^dep/', '^dependabot/']
+  - head-branch: ['^deps/', '^dep/', '^dependabot/', 'pre-commit-ci-update-config']
   - changed-files: ['go.mod', 'go.sum']