This change corrects problems reported by the `yamllint` linter.
Since key duplication problems were removed in 4d48711, this commit
mainly fixes trailing spaces and extra empty lines at beginning/end of
files.
* Add tag verification test (ansible-modules-core PR 2654)
* Fix typo
* Use smaller repo for testing, add dependency control
* Test is gpg exists before running git signing tasks
* Correct the test conditionals so that gpg1 is tested