Bump semigroups to 1.19

Author: jaspervdj

stylish-haskell.cabal

@@ -58,7 +58,7 @@ Library
     file-embed       >= 0.0.10 && < 0.1,
     haskell-src-exts >= 1.18   && < 1.22,
     mtl              >= 2.0    && < 2.3,
-    semigroups       >= 0.18   && < 0.19,
+    semigroups       >= 0.18   && < 0.20,
     syb              >= 0.3    && < 0.8,
     yaml             >= 0.8.11 && < 0.12