Bump com.github.spotbugs in the gradle-dependencies group

Bumps the gradle-dependencies group with 1 update: com.github.spotbugs.


Updates `com.github.spotbugs` from 6.0.8 to 6.0.13

---
updated-dependencies:
- dependency-name: com.github.spotbugs
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: gradle-dependencies
...

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

build.gradle

@@ -14,7 +14,7 @@ plugins {
     // Checkstyle enforces consistent formatting rules across the project.
     id 'checkstyle'
     // Spotbugs is a static analyzer for java
-    id 'com.github.spotbugs' version '6.0.8'
+    id 'com.github.spotbugs' version '6.0.13'
     // With this plugin, we can build a Windows executable
     id 'edu.sc.seis.launch4j' version '3.0.5'
 }