chore(deps): pin oven-sh/setup-bun action to v2 (#279)

This PR contains the following updates:

| Package | Type | Update | Change | OpenSSF |
|---|---|---|---|---|
| [oven-sh/setup-bun](https://redirect.github.com/oven-sh/setup-bun) |
action | pin | `v2` → `v2` | [![OpenSSF
Scorecard](https://api.securityscorecards.dev/projects/github.com/oven-sh/setup-bun/badge)](https://securityscorecards.dev/viewer/?uri=github.com/oven-sh/setup-bun)
|

Add the preset `:preserveSemverRanges` to your config if you don't want
to pin your dependencies.

---

### Configuration

📅 **Schedule**: (UTC)

- Branch creation
  - At any time (no schedule defined)
- Automerge
  - At any time (no schedule defined)

🚦 **Automerge**: Enabled.

♻ **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://mend.io/renovate/).
View the [repository job
log](https://developer.mend.io/github/settlemint/network-bootstrapper).

<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiI0My4xMzkuNyIsInVwZGF0ZWRJblZlciI6IjQzLjEzOS43IiwidGFyZ2V0QnJhbmNoIjoibWFpbiIsImxhYmVscyI6WyJkZXBlbmRlbmNpZXMiXX0=-->

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

Author: renovate[bot]

.github/workflows/qa.yml

@@ -90,7 +90,7 @@ jobs:
           slack_channel_id: ${{ env.SLACK_CHANNEL_ID }}
 
       - name: Setup Bun
-        uses: oven-sh/setup-bun@v2
+        uses: oven-sh/setup-bun@0c5077e51419868618aeaa5fe8019c62421857d6 # v2
         with:
           bun-version: latest