chore(deps): update rust docker tag to v1.76 (#386)

[![Mend
Renovate](https://app.renovatebot.com/images/banner.svg)](https://renovatebot.com)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| rust | stage | minor | `1.75` -> `1.76` |

---

### Configuration

📅 **Schedule**: Branch creation - At any time (no schedule defined),
Automerge - At any time (no schedule defined).

🚦 **Automerge**: Disabled by config. Please merge this manually once you
are satisfied.

♻ **Rebasing**: Whenever PR becomes conflicted, or you tick the
rebase/retry checkbox.

🔕 **Ignore**: Close this PR and you won't be reminded about this update
again.

---

- [ ] <!-- rebase-check -->If you want to rebase/retry this PR, check
this box

---

This PR has been generated by [Mend
Renovate](https://www.mend.io/free-developer-tools/renovate/). View
repository job log
[here](https://developer.mend.io/github/matter-labs/zksync-withdrawal-finalizer).

<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiIzNy4xNzMuMCIsInVwZGF0ZWRJblZlciI6IjM3LjE3My4wIiwidGFyZ2V0QnJhbmNoIjoibWFpbiJ9-->

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Dockerfile

@@ -1,4 +1,4 @@
-FROM rust:1.75 AS builder
+FROM rust:1.76 AS builder
 
 WORKDIR /app