build(deps): Bump ch.qos.logback:logback-core

Bumps [ch.qos.logback:logback-core](https://github.com/qos-ch/logback) from 1.2.3 to 1.3.15.
- [Release notes](https://github.com/qos-ch/logback/releases)
- [Commits](qos-ch/logback@v_1.2.3...v_1.3.15)

---
updated-dependencies:
- dependency-name: ch.qos.logback:logback-core
  dependency-version: 1.3.15
  dependency-type: direct:production
...

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

Author: dependabot[bot]

sentinel-demo/sentinel-demo-log-logback/pom.xml

@@ -25,7 +25,7 @@
         <dependency>
             <groupId>ch.qos.logback</groupId>
             <artifactId>logback-core</artifactId>
-            <version>1.2.3</version>
+            <version>1.3.15</version>
         </dependency>
 
         <dependency>