Update dependency Prometheus.Client.AspNetCore to v2.2.0 (#421)

This PR contains the following updates:

| Package | Type | Update | Change | References |
|---|---|---|---|---|
| Prometheus.Client.AspNetCore | nuget | minor | `2.1.0` -> `2.2.0` | [source](https://togithub.com/PrometheusClientNet/Prometheus.Client.AspNetCore) |

---

### Release Notes

<details>
<summary>PrometheusClientNet/Prometheus.Client.AspNetCore</summary>

### [`v2.2.0`](https://togithub.com/PrometheusClientNet/Prometheus.Client.AspNetCore/releases/2.2.0)

[Compare Source](https://togithub.com/PrometheusClientNet/Prometheus.Client.AspNetCore/compare/2.1.0...2.2.0)

-   [#&#8203;1] Add optional port restriction for /metrics endpoint
-   Actualize dependency: support Prometheus.Client (>= 2.0.0 && &lt; 3.0.0)

</details>

---

### Renovate configuration

:date: **Schedule**: At any time (no schedule defined).

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

:recycle: **Rebasing**: Whenever PR becomes conflicted, or if you modify the PR title to begin with "`rebase!`".

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

---

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

---

This PR has been generated by [Renovate Bot](https://togithub.com/marketplace/renovate). View repository job log [here](https://renovatebot.com/dashboard#tomkerkhove/promitor).

src/Promitor.Scraper.Host/Promitor.Scraper.Host.csproj

@@ -35,7 +35,7 @@
   <ItemGroup>
     <PackageReference Include="CronScheduler.AspNetCore" Version="1.0.11" />
     <PackageReference Include="Microsoft.AspNetCore.App" Version="2.2.3" />
-    <PackageReference Include="Prometheus.Client.AspNetCore" Version="2.1.0" />
+    <PackageReference Include="Prometheus.Client.AspNetCore" Version="2.2.0" />
     <PackageReference Include="Swashbuckle.AspNetCore" Version="4.0.1" />
     <PackageReference Include="Swashbuckle.AspNetCore.Annotations" Version="4.0.1" />
     <PackageReference Include="System.Net.Http" Version="4.3.4" />