CI: add hlint workflow#2537

mergify[bot] merged 5 commits intohaskell:masterhaskell/haskell-language-server:masterfrom

Anton-Latukha:2021-12-25-add-hlint-workflowAnton-Latukha/haskell-language-server:2021-12-25-add-hlint-workflowCopy head branch name to clipboard