Feature request: Run updates locally

[infinisil]

I'd like to have an easy command to run updates locally, such that the local files are updated as if all resulting dependabot PRs were merged.

This might look like

dependabot local-update github_actions .

resulting in

diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 233d7dd..36d9200 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -8,7 +8,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - uses: cachix/install-nix-action@v26

It's currently possible to do that, but it requires some extra machinery that I'd rather avoid, see this script.