chore(deps): update golang docker tag to v1.23 (#1535)

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

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| golang | final | minor | `1.22-alpine` -> `1.23-alpine` |

---

### Configuration

📅 **Schedule**: Branch creation - "before 4am on Monday" in timezone America/Los_Angeles, Automerge - At any time (no schedule defined).

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

♻ **Rebasing**: Whenever PR is behind base branch, 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 was generated by [Mend Renovate](https://www.mend.io/free-developer-tools/renovate/). View the [repository job log](https://developer.mend.io/github/googleapis/gapic-showcase).
<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiIzOC4yNi4xIiwidXBkYXRlZEluVmVyIjoiMzguMjYuMSIsInRhcmdldEJyYW5jaCI6Im1haW4iLCJsYWJlbHMiOlsiYXV0b21lcmdlIl19-->

Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.22-alpine AS builder
+FROM golang:1.23-alpine AS builder
 
 # Install git and gcc.
 RUN apk add --no-cache git gcc musl-dev