Create a small Groovy script that can be used in `settings.gradle`
files to extend `repositories` to support the various maven
repositories required for our build.
See gh-42333
Update `spring-boot-loader-tests` with a test that checks verified
BouncyCastle jars can be loaded. Currently the Oracle JDK only supports
verification if the jar is unpacked.
See gh-28837
Replace Gradle single quote strings with the double quote form
whenever possible. The change helps to being consistency to the
dependencies section where mostly single quotes were used, but
occasionally double quotes were required due to `${}` references.