Bump Cabal upper bound to 3.1

Author: jaspervdj

stack.yaml

@@ -1,3 +1,6 @@
 resolver: lts-14.6
 packages:
-  - '.'
+- '.'
+
+extra-deps:
+- 'Cabal-3.0.0.0'

stylish-haskell.cabal

@@ -54,7 +54,7 @@ Library
     aeson            >= 0.6    && < 1.5,
     base             >= 4.8    && < 5,
     bytestring       >= 0.9    && < 0.11,
-    Cabal            >= 2.4    && < 2.5,
+    Cabal            >= 2.4    && < 3.1,
     containers       >= 0.3    && < 0.7,
     directory        >= 1.2.3  && < 1.4,
     filepath         >= 1.1    && < 1.5,
@@ -78,7 +78,7 @@ Executable stylish-haskell
     aeson            >= 0.6    && < 1.5,
     base             >= 4.8    && < 5,
     bytestring       >= 0.9    && < 0.11,
-    Cabal            >= 2.4    && < 2.5,
+    Cabal            >= 2.4    && < 3.1,
     containers       >= 0.3    && < 0.7,
     directory        >= 1.2.3  && < 1.4,
     filepath         >= 1.1    && < 1.5,
@@ -132,7 +132,7 @@ Test-suite stylish-haskell-tests
     aeson            >= 0.6    && < 1.5,
     base             >= 4.8    && < 5,
     bytestring       >= 0.9    && < 0.11,
-    Cabal            >= 2.4    && < 2.5,
+    Cabal            >= 2.4    && < 3.1,
     containers       >= 0.3    && < 0.7,
     directory        >= 1.2.3  && < 1.4,
     filepath         >= 1.1    && < 1.5,