chore: add e2e go.mod to dependabot

[colin-axner]

Description

I noticed dependabot updates to main never run go mod tidy in the e2e directory, I wonder if this would fix it or open 2 pr's?

closes: #XXXX

Commit Message / Changelog Entry

type: commit message

see the guidelines for commit messages. (view raw markdown for examples)

---

Before we can merge this PR, please make sure that all the following items have been
checked off. If any of the checklist items are not applicable, please leave them but
write a little note why.

• Targeted PR against correct branch (see CONTRIBUTING.md).
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Code follows the module structure standards and Go style guide.
• Wrote unit and integration tests.
• Updated relevant documentation (docs/) or specification (x/<module>/spec/).
• Added relevant godoc comments.
• Provide a commit message to be used for the changelog entry in the PR description for review.
• Re-reviewed Files changed in the Github PR explorer.
• Review Codecov Report in the comment section below once CI passes.

[colin-axner]

I think we should probably add this workflow https://github.com/cosmos/cosmos-sdk/blob/main/.github/workflows/dependabot-update-all.yml?

[damiannolan]

I think we should probably add this workflow https://github.com/cosmos/cosmos-sdk/blob/main/.github/workflows/dependabot-update-all.yml?

Seems like probably a good idea considering we'll likely have more go mods