Update .gitignore

Use current GitHub standard `Haskell.gitignore`, adding `stack.yaml`:
https://github.com/github/gitignore/blob/master/Haskell.gitignore

Author: akhra

.gitignore

@@ -1,8 +1,20 @@
-dist/
-*.hi
+dist
+dist-*
+cabal-dev
 *.o
-*.dyn_hi
+*.hi
+*.chi
+*.chs.h
 *.dyn_o
-*~
-.hsenv/
-TAGS
+*.dyn_hi
+.hpc
+.hsenv
+.cabal-sandbox/
+cabal.sandbox.config
+*.prof
+*.aux
+*.hp
+*.eventlog
+.stack-work/
+cabal.project.local
+stack.yaml