🐛 Add back support for Java 17

Closes #22

Author: Lezurex

build.gradle

@@ -11,10 +11,18 @@ repositories {
 }
 
 java {
+    toolchain {
+        languageVersion = JavaLanguageVersion.of(21)
+    }
     withJavadocJar()
     withSourcesJar()
 }
 
+tasks.withType(JavaCompile) {
+    sourceCompatibility = '17'
+    targetCompatibility = '17'
+}
+
 dependencies {
     implementation 'com.google.code.gson:gson:2.11.0'