Bump lombok from 1.18.16 to 1.18.20

Bumps lombok from 1.18.16 to 1.18.20.

Changelog

Sourced from lombok's changelog.

v1.18.20 (April 2nd, 2021)

• PLATFORM: JDK16 support added. [Issue #2681](https://github.com/rzwitserloot/lombok/issues/2681).
• PLATFORM: All lombok features updated to act in a sane fashion with JDK16's record feature. In particular, you can annotate record components with @NonNull to have lombok add null checks to your compact constructor (which will be created if need be).
• BUGFIX: Trying to use a lambda expression as parameter to an @ExtensionMethod did not work. [Issue #2741](https://github.com/rzwitserloot/lombok/issues/2741). (by @Rawi01).
• BUGFIX: @SuperBuilder with an existing constructor caused issues in eclipse. [Issue #2704](https://github.com/rzwitserloot/lombok/issues/2704). (by @JanRieke).
• BUGFIX: Using @SuperBuilder with a handwritten builder class caused issues. [Issue #2701](https://github.com/rzwitserloot/lombok/issues/2701). (by @JanRieke).
• BUGFIX: Lombok interacts properly with the new save actions in eclipse 2021-03.
• POTENTIAL BUGFIX: lombok + errorprone could cause IllegalArgumentException if using the MissingSummary bug pattern. [Issue #2730](https://github.com/rzwitserloot/lombok/issues/2730).

v1.18.18 (January 28th, 2021)

• BUGFIX: Various tools using ecj under the hood (including intellij) could cause corrupt class files to be generated. [PR #2637](https://github.com/rzwitserloot/lombok/pull/2637), [lombok-intellij-plugin issue #969](https://github.com/mplushnikov/lombok-intellij-plugin/issues/969).
• BUGFIX: Netbeans would not work with 1.18.16 anymore. [Issue #2612](https://github.com/rzwitserloot/lombok/issues/2612).
• BUGFIX: @ExtensionMethod support in ecj improved when generics are involved. [Issue #2648](https://github.com/rzwitserloot/lombok/issues/2648), [PR #2658](https://github.com/rzwitserloot/lombok/pull/2658) thanks to @Rawi01.
• PLATFORM: using lombok.config files when compiling with sbt 1.4 now works again. [Issue #2645](https://github.com/rzwitserloot/lombok/issues/2645)

Commits

• dda76a7 [versioning] pre-release version bump
• 0fb3a68 [build] fix the website maker's all-versions tool
• ff8af61 Fixes #2803 Manual merge, hide generated code from some Eclipse refactorings
• 72d9bfc [docker] upgrade gradle (no jdk16 support yet)
• baabbd2 [docker] update maven
• a9adc23 [docker] upgrade ant
• 4637b9d [record] Print compact constructor after class name
• 462aedc [fixes #2787] Handle right hand side of assignment first
• 9b3e847 Merge pull request #2793 from Rawi01/license
• dc2b3c8 Add licenses of embedded dependencies
• Additional commits viewable in compare view