chore(deps): Update actions/setup-dotnet action to v5 (#78)

> [!NOTE]
> Mend has cancelled [the proposed
renaming](https://redirect.github.com/renovatebot/renovate/discussions/37842)
of the Renovate GitHub app being renamed to `mend[bot]`.
> 
> This notice will be removed on 2025-10-07.

<hr>

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
|
[actions/setup-dotnet](https://redirect.github.com/actions/setup-dotnet)
| action | major | `v4` -> `v5` |

---

### Release Notes

<details>
<summary>actions/setup-dotnet (actions/setup-dotnet)</summary>

###
[`v5`](https://redirect.github.com/actions/setup-dotnet/compare/v4...v5)

[Compare
Source](https://redirect.github.com/actions/setup-dotnet/compare/v4...v5)

</details>

---

### Configuration

📅 **Schedule**: Branch creation - Between 12:00 AM and 03:59 AM, on day
1 of the month ( * 0-3 1 * * ) (UTC), Automerge - At any time (no
schedule defined).

🚦 **Automerge**: Enabled.

♻ **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 was generated by [Mend Renovate](https://mend.io/renovate/).
View the [repository job
log](https://developer.mend.io/github/hypermodeinc/dgraph.net).

<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiI0MS4xMzEuOSIsInVwZGF0ZWRJblZlciI6IjQxLjEzMS45IiwidGFyZ2V0QnJhbmNoIjoibWFpbiIsImxhYmVscyI6W119-->

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

Author: renovate[bot]

.github/workflows/ci-dgraph-net-e2e-tests.yml

@@ -31,7 +31,7 @@ jobs:
         uses: actions/checkout@v5
 
       - name: Setup .NET Core SDK
-        uses: actions/setup-dotnet@v4
+        uses: actions/setup-dotnet@v5
         with:
           dotnet-version: 8.0.x
 

.github/workflows/ci-dgraph-net-tests.yml

@@ -27,7 +27,7 @@ jobs:
         uses: actions/checkout@v5
 
       - name: Setup .NET Core SDK
-        uses: actions/setup-dotnet@v4
+        uses: actions/setup-dotnet@v5
         with:
           dotnet-version: 8.0.x