chore: Limit aeson version compatibility.

aeson 2 introduced incompatible changes.

Author: iphydf

github-tools.cabal

@@ -115,7 +115,7 @@ library
   default-language:    Haskell2010
   build-depends:
       base >= 4 && < 5
-    , aeson             >= 0.8.1.0
+    , aeson             >= 0.8.1.0 && < 2
     , bytestring
     , containers
     , cryptohash