chore: release 2.2.4 (#378)

🤖 I have created a release \*beep\* \*boop\* 
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### [2.2.4](https://www.github.com/googleapis/java-dlp/compare/v2.2.3...v2.2.4) (2020-12-14)


### Dependencies

* update dependency com.google.cloud:google-cloud-shared-dependencies to v0.16.1 ([#376](https://www.github.com/googleapis/java-dlp/issues/376)) ([163bb4e](https://www.github.com/googleapis/java-dlp/commit/163bb4e6447513aa6d3df681fa074b7ac3c05e6f))
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This PR was generated with [Release Please](https://github.com/googleapis/release-please).

Author: release-please[bot]

dlp/snippets/snapshot/pom.xml

@@ -28,7 +28,7 @@
     <dependency>
       <groupId>com.google.cloud</groupId>
       <artifactId>google-cloud-dlp</artifactId>
-      <version>2.2.4-SNAPSHOT</version>
+      <version>2.2.4</version>
     </dependency>
     <!-- {x-version-update-end} -->