fix(deps): update dependency com.google.cloud:cloud-spanner-r2dbc to v1.2.1 (GoogleCloudPlatform#8048)

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

This PR contains the following updates:

| Package | Change | Age | Adoption | Passing | Confidence |
|---|---|---|---|---|---|
| [com.google.cloud:cloud-spanner-r2dbc](https://togithub.com/GoogleCloudPlatform/cloud-spanner-r2dbc/tree/main/cloud-spanner-r2dbc) ([source](https://togithub.com/GoogleCloudPlatform/cloud-spanner-r2dbc)) | `1.2.0` -> `1.2.1` | [![age](https://badges.renovateapi.com/packages/maven/com.google.cloud:cloud-spanner-r2dbc/1.2.1/age-slim)](https://docs.renovatebot.com/merge-confidence/) | [![adoption](https://badges.renovateapi.com/packages/maven/com.google.cloud:cloud-spanner-r2dbc/1.2.1/adoption-slim)](https://docs.renovatebot.com/merge-confidence/) | [![passing](https://badges.renovateapi.com/packages/maven/com.google.cloud:cloud-spanner-r2dbc/1.2.1/compatibility-slim/1.2.0)](https://docs.renovatebot.com/merge-confidence/) | [![confidence](https://badges.renovateapi.com/packages/maven/com.google.cloud:cloud-spanner-r2dbc/1.2.1/confidence-slim/1.2.0)](https://docs.renovatebot.com/merge-confidence/) |

---

### ⚠ Dependency Lookup Warnings ⚠

Warnings were logged while processing this repo. Please check the Dependency Dashboard for more information.

---

### Release Notes

<details>
<summary>GoogleCloudPlatform/cloud-spanner-r2dbc</summary>

### [`v1.2.1`](https://togithub.com/GoogleCloudPlatform/cloud-spanner-r2dbc/blob/HEAD/CHANGELOG.md#&#8203;121-httpsgithubcomGoogleCloudPlatformcloud-spanner-r2dbccomparev120v121-2023-05-12)

[Compare Source](https://togithub.com/GoogleCloudPlatform/cloud-spanner-r2dbc/compare/v1.2.0...v1.2.1)

##### Bug Fixes

-   row column indexing in SpannerClientLibraryRow ([#&GoogleCloudPlatform#8203;615](https://togithub.com/GoogleCloudPlatform/cloud-spanner-r2dbc/issues/615)) ([faca504](https://togithub.com/GoogleCloudPlatform/cloud-spanner-r2dbc/commit/faca50457615359da2766641aa2cccb916558bd9)), closes [#&GoogleCloudPlatform#8203;609](https://togithub.com/GoogleCloudPlatform/cloud-spanner-r2dbc/issues/609)

</details>

---

### 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**: Never, 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://app.renovatebot.com/dashboard#github/GoogleCloudPlatform/java-docs-samples).
<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiIzNS40OC4yIiwidXBkYXRlZEluVmVyIjoiMzUuNDguMiJ9-->

Author: renovate-bot

spanner/r2dbc/pom.xml

@@ -61,7 +61,7 @@
     <dependency>
       <groupId>com.google.cloud</groupId>
       <artifactId>cloud-spanner-r2dbc</artifactId>
-      <version>1.2.0</version>
+      <version>1.2.1</version>
     </dependency>
     <!-- [END spanner_r2dbc_dependency] -->