Following the fix for gh-21989, spring-boot-starter-parent no longer
contains an <issueManagement> element. As a result the additional
content was no longer being added to the pom. This commit updates
the additions so that they are now added after the <scm> element
that is still present.
See gh-21989
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.
