chore(deps): update dependency com.google.cloud:google-cloud-spanner to v1.52.0 (#2452)

This PR contains the following updates:

| Package | Update | Change |
|---|---|---|
| [com.google.cloud:google-cloud-spanner](https://github.com/googleapis/java-spanner) | minor | `1.51.0` -> `1.52.0` |

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### Release Notes

<details>
<summary>googleapis/java-spanner</summary>

### [`v1.52.0`](https://github.com/googleapis/java-spanner/blob/master/CHANGELOG.md#&#8203;1520httpswwwgithubcomgoogleapisjava-spannercomparev1510v1520-2020-03-20)

[Compare Source](https://github.com/googleapis/java-spanner/compare/v1.51.0...v1.52.0)

##### Features

-   add backup support ([#&#8203;100](https://www.github.com/googleapis/java-spanner/issues/100)) ([ed3874a](https://www.github.com/googleapis/java-spanner/commit/ed3874afcf55fe7381354e03dab3a3b97d7eb520))
-   add Backups protos and APIs ([#&#8203;97](https://www.github.com/googleapis/java-spanner/issues/97)) ([5643c22](https://www.github.com/googleapis/java-spanner/commit/5643c22a4531dac75b9fac5b128eb714a27920a0))

##### Bug Fixes

-   add client id to metrics to avoid collisions ([#&#8203;117](https://www.github.com/googleapis/java-spanner/issues/117)) ([338e136](https://www.github.com/googleapis/java-spanner/commit/338e136508edc6745f9371e8a5d66638021bc8d7)), closes [#&#8203;106](https://www.github.com/googleapis/java-spanner/issues/106)
-   ignore added interface methods for generated code ([#&#8203;101](https://www.github.com/googleapis/java-spanner/issues/101)) ([402cfa1](https://www.github.com/googleapis/java-spanner/commit/402cfa1e1e2994f7bb1b783cf823021b54fb175e)), closes [#&#8203;99](https://www.github.com/googleapis/java-spanner/issues/99)
-   use grpc 1.27.2 to prevent version conflicts ([#&#8203;105](https://www.github.com/googleapis/java-spanner/issues/105)) ([37b7c88](https://www.github.com/googleapis/java-spanner/commit/37b7c8859e5f35d85bd14ef72662614fd185c020))

##### Dependencies

-   update core dependencies ([#&#8203;94](https://www.github.com/googleapis/java-spanner/issues/94)) ([f3ca4c9](https://www.github.com/googleapis/java-spanner/commit/f3ca4c99c3d54f64c5eda11e4a4c076140fdbc6a))
-   update opencensus.version to v0.26.0 ([#&#8203;116](https://www.github.com/googleapis/java-spanner/issues/116)) ([1b8db0b](https://www.github.com/googleapis/java-spanner/commit/1b8db0b407429e02bb1e4c9af839afeed21dac5d))

</details>

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Author: renovate-bot

appengine-java8/spanner/pom.xml

@@ -44,7 +44,7 @@
     <dependency>
       <groupId>com.google.cloud</groupId>
       <artifactId>google-cloud-spanner</artifactId>
-      <version>1.51.0</version>
+      <version>1.52.0</version>
     </dependency>
     <dependency>
       <groupId>javax.servlet</groupId>