Bump com.gradle.plugin-publish from 0.18.0 to 0.20.0

Bumps com.gradle.plugin-publish from 0.18.0 to 0.20.0.

---
updated-dependencies:
- dependency-name: com.gradle.plugin-publish
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

build.gradle

@@ -4,7 +4,7 @@ import static java.lang.Integer.parseInt
 
 plugins {
     id 'nu.studer.plugindev' version '4.1'
-    id 'com.gradle.plugin-publish' version '0.18.0'
+    id 'com.gradle.plugin-publish' version '0.20.0'
     id 'org.nosphere.gradle.github.actions' version '1.3.2'
     id 'groovy'
 }