Clarify changelog about JSR305 changes

While LearnLib (via AutomataLib) currently still has a compile-time dependency on JSR305 annotations on JDKs >= 11, ef4dc4d removed them from hand-written code and from transitive dependencies of third party libraries (mainly Guava).

Since annotations that are not available at runtime are simply ignored by the JRE (treated as if the class/method/etc. was not annotated), this change alone allows us to effectively drop the dependency for user-land code without further consequences even if it is still referenced in (transitive) code.

Author: mtf90

CHANGELOG.md

@@ -12,6 +12,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 * The `{DFA,Mealy,}W{p,}MethodEQOracle(MembershipOracle, int, int)` constructor no longer interprets its second `int` parameter as the batch size, but as an estimate for the expected SUL size. In order to explicitly set the batch size of the oracle, use the `{DFA,Mealy,}W{p,}MethodEQOracle(MembershipOracle, int, int, int)` constructor. Now, the two parameters `lookahead` and `expectedSize` will determine the length of the *middle part* via `Math.max(lookahead, expectedSize - hypothesis.size())`. This allows to dynamically adjust the length of the *middle part* throughout the learning process. See [LearnLib/automatalib#32](https://github.com/LearnLib/automatalib/issues/32).
 * Several DFA/Mealy specific (oracle) subclasses are now automatically generated. As a result they are no longer an inner class, but an indepentend top-level class. This requires to update the import statements.
+* JSR305 annotations have been replaced with checker-framework annotations.
+  * LearnLib (incl. AutomataLib) now follows checker-framework's convention that (non-annotated) types are usually considered non-null unless explicitly annotated with `@Nullable`.
+  * LearnLib (incl. AutomataLib) no longer has a (runtime-) dependency on JSR305 (and other `javax.*`) annotations or includes them in the distribution artifact. This now makes LearnLib (incl. AutomataLib) compliant with [Oracle's binary code license](https://www.oracle.com/downloads/licenses/binary-code-license.html) and allows LearnLib (incl. AutomataLib) artifacts as-is to be bundled in binary distributions with Oracle's JDKs/JREs.
 
 ### Removed