Update Gradle Wrapper 8.5 to 8.7

[beatngu13]

At the moment, the build causes a new warning because of:

https://docs.gradle.org/current/userguide/upgrading_version_8.html#deprecate_register_feature_main_source_set

I first have to read through this, which is why I marked this PR as a draft. Simply doing the changes suggested in the Gradle docs:

--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -29,6 +29,12 @@ val releaseBuild : Boolean = project.version != "unspecified"
 
 val targetJavaVersion = JavaVersion.VERSION_11
 
+val jacksonFeature = "jackson"
+
+sourceSets {
+       create(jacksonFeature)
+}
+
 java {
        if (experimentalBuild) {
                toolchain {
@@ -39,8 +45,8 @@ java {
        }
        withJavadocJar()
        withSourcesJar()
-       registerFeature("jackson") {
-               usingSourceSet(sourceSets["main"])
+       registerFeature(jacksonFeature) {
+               usingSourceSet(sourceSets[jacksonFeature])
        }
 }

Yields 2 errors due to our modular setup:

> Task :compileJava FAILED
/Users/kruse/dev/workspaces/private/junit-pioneer/src/main/java/module-info.java:18: error: module not found: com.fasterxml.jackson.core
        requires static com.fasterxml.jackson.core;
                                             ^
/Users/kruse/dev/workspaces/private/junit-pioneer/src/main/java/module-info.java:19: error: module not found: com.fasterxml.jackson.databind
        requires static com.fasterxml.jackson.databind;
                                             ^
2 errors

Proposed commit message:

Update Gradle Wrapper to 8.5 to 8.7 (#807)

See: https://github.com/gradle/gradle/releases/tag/v8.7.0

PR: #807

---

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[Bukama]

Hm Jackson should already been buildable with the moditec file (FasterXML/jackson-databind#2273) which is labeled as implemented in 2.10 (we are using 2.14) 🤔