Changelog for Groovy 2.4.21

Bug

[GROOVY-9704] - The '~' negate operator causes an ASM processing error when static compiled
[GROOVY-9818] - JSP-API license seems to be missing
[GROOVY-9824] - replace some old api usage with newer available variants
[GROOVY-9826] - Better propagation of InterruptedException

[GROOVY-9552] - Bump Ant versions to address: [CVE-2020-1945] Apache Ant insecure temporary file vulnerability
[GROOVY-9793] - Bump JUnit4 version to 4.13.1 (includes security fix)