chore(deps): update dependency ch.qos.logback:logback-classic to v1.3.0-alpha6 (GoogleCloudPlatform#5704)

Author: renovate-bot

appengine-java11/kotlin-ktor/pom.xml

@@ -79,7 +79,7 @@ limitations under the License.
     <dependency>
       <groupId>ch.qos.logback</groupId>
       <artifactId>logback-classic</artifactId>
-      <version>1.3.0-alpha5</version>
+      <version>1.3.0-alpha6</version>
     </dependency>
     <dependency>
       <groupId>io.ktor</groupId>

run/hello-broken/pom.xml

@@ -41,7 +41,7 @@ limitations under the License.
     <dependency>
       <groupId>ch.qos.logback</groupId>
       <artifactId>logback-classic</artifactId>
-      <version>1.3.0-alpha5</version>
+      <version>1.3.0-alpha6</version>
     </dependency>
     <dependency>
       <groupId>org.slf4j</groupId>