Add JSpecify

Author: marcphilipp

junit-modular-world/src/build/Project.java

@@ -56,6 +56,7 @@ void compile() throws Exception {
     get("lib", "junit", "junit", "4.13.2");
     get("lib", "org.hamcrest", "hamcrest-core", "1.3");
     get("lib", "org.apiguardian", "apiguardian-api", "1.1.2");
+    get("lib", "org.jspecify", "jspecify", "1.0.0");
     get("lib", "org.opentest4j", "opentest4j", "1.3.0");
     get("lib", "org.opentest4j.reporting", "open-test-reporting-tooling-spi", "0.2.3");
     get("lib", "net.jqwik", "jqwik-api", "1.9.3");