fix: fix compatability with jdk-16

add work around for gradle spotless plugin
see details at: diffplug/spotless#693

Author: connoratrug

gradle.properties

@@ -1,2 +1,6 @@
 org.gradle.parallel=true
-org.gradle.jvmargs=-Xmx2048M
+org.gradle.jvmargs=-Xmx2048M --add-exports jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED \
+  --add-exports jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED \
+  --add-exports jdk.compiler/com.sun.tools.javac.parser=ALL-UNNAMED \
+  --add-exports jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED \
+  --add-exports jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED