chore: release 0.121.13 (#529)

🤖 I have created a release \*beep\* \*boop\*
---
### [0.121.13](https://www.github.com/googleapis/java-logging-logback/compare/v0.121.12...v0.121.13) (2021-09-13)


### Dependencies

* update logback.version to v1.2.6 ([#528](https://www.github.com/googleapis/java-logging-logback/issues/528)) ([1be3b8a](https://www.github.com/googleapis/java-logging-logback/commit/1be3b8ade768b211128918a159cf092d38c0c8fd))
---


This PR was generated with [Release Please](https://github.com/googleapis/release-please). See [documentation](https://github.com/googleapis/release-please#release-please).

CHANGELOG.md

@@ -1,5 +1,12 @@
 # Changelog
 
+### [0.121.13](https://www.github.com/googleapis/java-logging-logback/compare/v0.121.12...v0.121.13) (2021-09-13)
+
+
+### Dependencies
+
+* update logback.version to v1.2.6 ([#528](https://www.github.com/googleapis/java-logging-logback/issues/528)) ([1be3b8a](https://www.github.com/googleapis/java-logging-logback/commit/1be3b8ade768b211128918a159cf092d38c0c8fd))
+
 ### [0.121.12](https://www.github.com/googleapis/java-logging-logback/compare/v0.121.11...v0.121.12) (2021-09-03)
 
 

pom.xml

@@ -5,7 +5,7 @@
   <modelVersion>4.0.0</modelVersion>
 
   <artifactId>google-cloud-logging-logback</artifactId>
-  <version>0.121.13-alpha-SNAPSHOT</version><!-- {x-version-update:google-cloud-logging-logback:current} -->
+  <version>0.121.13-alpha</version><!-- {x-version-update:google-cloud-logging-logback:current} -->
   <packaging>jar</packaging>
   <name>Google Cloud Logging Logback Appender</name>
   <url>https://github.com/googleapis/java-logging-logback</url>

versions.txt

@@ -1,4 +1,4 @@
 # Format:
 # module:released-version:current-version
 
-google-cloud-logging-logback:0.121.12-alpha:0.121.13-alpha-SNAPSHOT
+google-cloud-logging-logback:0.121.13-alpha:0.121.13-alpha