allow "gradle build -PjavacRelease=17" to build java-17 binary

for gradle now one could do:
gradle clean build -x test -x javaDoc -PjavacRelease=17

for maven something like this works to build a different target binary:
mvn clean package -Dmaven.test.skip=true -Dmaven.javadoc.skip=true -Dmaven.compiler.release=17

build.gradle.kts

@@ -1,3 +1,5 @@
+val javacRelease: String by project
+
 plugins {
   java
   `maven-publish`
@@ -50,7 +52,7 @@ sourceSets {
 }
 
 tasks.compileJava {
-	options.release.set(8)
+	options.release.set(Integer.parseInt(javacRelease))
 }
 
 tasks.withType<Jar> {

gradle.properties

@@ -1 +1,2 @@
+javacRelease = 8
 version = 1.2022.1-SNAPSHOT