GitLab

* [R-package] improvements to lgb.convert() functions (fixes #2678, #2681)

* more stuff

* update docs

* remove lgb.convert()

* put internal functions back

* update index

* [R-package] deprecate lgb.prepare() and lgb.prepare2()

* linting

* renaming

* updated docs

* linting

* Apply suggestions from code review
Co-authored-by: Nikita Titov <nekit94-08@mail.ru>

* one more comment fix

* remove comment about int being dangerous

* empty commit
Co-authored-by: Nikita Titov <nekit94-08@mail.ru>

* [R-package] [docs] fix warnings in pkgdown sitte  building

* trying to get better Travis logs

* trying to get better Travis logs

* undo testing fix

* undo testing fix

* empty commit

* [R-package] [docs] remove devtools dependency for docs builds

* linting

* updating docs conda env

* empty roxygenize()

* env for R libraries

* get logs

* remove comment

* added pkgdown URLs

* more paths

* fix incorrect YAML keys

* update DESCRIPTION URL link

* more URL changes

* revert DESCRIPTION changes

* remove ca-certificates

* empty commit

* Update docs/conf.py
Co-authored-by: Nikita Titov <nekit94-08@mail.ru>

* empty commit

* remove outdated line in build_r.R
Co-authored-by: Nikita Titov <nekit94-08@mail.ru>