Bump logback.version from 1.5.16 to 1.5.20

Bumps `logback.version` from 1.5.16 to 1.5.20.

Updates `ch.qos.logback:logback-core` from 1.5.16 to 1.5.20
- [Release notes](https://github.com/qos-ch/logback/releases)
- [Commits](qos-ch/logback@v_1.5.16...v_1.5.20)

Updates `ch.qos.logback:logback-classic` from 1.5.16 to 1.5.20
- [Release notes](https://github.com/qos-ch/logback/releases)
- [Commits](qos-ch/logback@v_1.5.16...v_1.5.20)

---
updated-dependencies:
- dependency-name: ch.qos.logback:logback-core
  dependency-version: 1.5.20
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: ch.qos.logback:logback-classic
  dependency-version: 1.5.20
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

secure-api-gateway-ig-extensions-ob/pom.xml

@@ -31,7 +31,7 @@
 
     <properties>
         <legal.path.header>../legal/LICENSE-HEADER.txt</legal.path.header>
-        <logback.version>1.5.16</logback.version>
+        <logback.version>1.5.20</logback.version>
     </properties>
 
     <dependencyManagement>