Bump Cabal-syntax to <3.12

Author: andreasabel

example-client/example-client.cabal

@@ -68,7 +68,7 @@ executable example-client
     build-depends: network     >= 2.5 && < 2.6
 
   if flag(Cabal-syntax)
-    build-depends: Cabal-syntax >= 3.7 && < 3.9
+    build-depends: Cabal-syntax >= 3.7 && < 3.12
   else
     build-depends: Cabal        >= 1.12 && < 3.7,
                    Cabal-syntax <  3.7

hackage-repo-tool/hackage-repo-tool.cabal

@@ -101,7 +101,7 @@ executable hackage-repo-tool
     build-depends: network     >= 2.5 && < 2.6
 
   if flag(Cabal-syntax)
-    build-depends: Cabal-syntax >= 3.7 && < 3.10
+    build-depends: Cabal-syntax >= 3.7 && < 3.12
   else
     build-depends: Cabal        >= 1.14    && < 1.26
                              || >= 2.0     && < 2.6

hackage-security/hackage-security.cabal

@@ -165,7 +165,7 @@ library
     build-depends:     base       >= 4.10
 
   if flag(Cabal-syntax) && impl(ghc >= 8.2)
-    build-depends: Cabal-syntax >= 3.7 && < 3.10
+    build-depends: Cabal-syntax >= 3.7 && < 3.12
   else
     build-depends: Cabal        >= 1.14    && < 1.26
                              || >= 2.0     && < 2.6