Restricts forma < 1.2.0 (#6217)

Author: jkachmar

build-constraints.yaml

@@ -2763,7 +2763,7 @@ packages:
         - cue-sheet
         - flac
         - flac-picture
-        - forma
+        - forma < 1.2.0 # https://github.com/commercialhaskell/stackage/issues/6217
         - ghc-syntax-highlighter
         - hspec-megaparsec
         - htaglib