Add an upper bound to scotty (#7208)

Signed-off-by: Mihai Maruseac <mihai.maruseac@gmail.com>

build-constraints.yaml

@@ -1169,7 +1169,7 @@ packages:
         - zlib-lens
 
     "Andrew Farmer <afarmer@ittc.ku.edu> @xich":
-        - scotty
+        - scotty < 0.21 # https://github.com/commercialhaskell/stackage/issues/7208
         - wai-middleware-static
 
     "Simon Hengel <sol@typeful.net> @sol":
@@ -5349,7 +5349,7 @@ packages:
         - bindings-DSL
         - bindings-uname
         - bitarray
-        - blank-canvas < 0
+        - blank-canvas
         - blaze-svg
         - blaze-textual
         - bloomfilter
@@ -5552,7 +5552,7 @@ packages:
         - json
         - json-alt
         - jsonrpc-tinyclient
-        - kansas-comet < 0
+        - kansas-comet
         - kleene
         - knob
         - language-haskell-extract