Fix #540

[arulrajnet]

Fix for #540 which was broken in #1119

• Take care of system and user config
• Now the defaultEndings follows the proper order https://github.com/diffplug/spotless/blob/main/lib-extra/src/main/java/com/diffplug/spotless/extra/GitAttributesLineEndings.java#L206

@nedtwigg Tested in local. Now the .gitconfig in user directory is taken care. Tested with SNAPSHOT build and it works. Is there anything else I have to update / test.

[nedtwigg]

Thanks for the PR!

https://app.circleci.com/pipelines/github/diffplug/spotless/1883/workflows/6f5f82a2-ab75-41ba-b208-b7abaaf57260/jobs/10757

Looks like tests aren't compiling. The criteria to get this merged and released are:

• fix tests, get them to pass (./gradlew testClasses and ./gradlew test)
• update all three changelogs with

## [Unreleased]
### Fixed
- blah blah blah

[arulrajnet]

@nedtwigg Done. The tests are passed now.

[arulrajnet]

@nedtwigg what is the next step? Gentle reminder.

[nedtwigg]

Sorry, thanks for the reminder!

[nedtwigg]

Released in plugin-gradle 6.4.2 and plugin-maven 2.22.1