Bump caffeine from 2.8.6 to 2.8.8

Bumps [caffeine](https://github.com/ben-manes/caffeine) from 2.8.6 to 2.8.8.
- [Release notes](https://github.com/ben-manes/caffeine/releases)
- [Commits](ben-manes/caffeine@v2.8.6...v2.8.8)

Signed-off-by: dependabot[bot] <support@github.com>

pom.xml

@@ -15,7 +15,7 @@
     <description>Twitter Retweet Bot</description>
 
     <properties>
-        <caffeine-version>2.8.6</caffeine-version>
+        <caffeine-version>2.8.8</caffeine-version>
         <ecs-logging-java-version>0.5.2</ecs-logging-java-version>
         <java.version>11</java.version>
         <maven-surefire-plugin-version>3.0.0-M5</maven-surefire-plugin-version>