CI: add GHC 9.14 to test matrix (#11910)

GHC 9.14 ships base 4.22 and containers 0.8, newer than the bounds of
serialise, cborg, and haddock-library allow.  Relax them under
impl(ghc >= 9.14) so other lanes are unaffected, and force -fhttp on
the 9.14 lane: given the choice, the solver prefers disabling the
http flag to violating bounds.

.github/workflows/ci.yml

@@ -64,6 +64,11 @@ jobs:
           - ghc: '9.12'
             cabal: 'latest'
             cabalopts: '--ghc-option=-Werror -f-embed_data_files'
+          - ghc: '9.14'
+            cabal: 'latest'
+            # -fhttp: on base 4.22 the solver otherwise prefers
+            # disabling the http flag to using allow-newer
+            cabalopts: '--ghc-option=-Werror -fhttp'
 
     steps:
     - uses: actions/checkout@v7

cabal.project

@@ -9,6 +9,14 @@ constraints: skylighting-format-blaze-html >= 0.1.2.2,
 
 allow-newer: hslua-module-zip:zip-archive,gridtables:doclayout,djot:doclayout,hslua-module-doclayout:doclayout
 
+-- GHC 9.14 ships base 4.22 and containers 0.8, which are newer than
+-- the upper bounds of these packages allow.
+if impl(ghc >= 9.14)
+  allow-newer: serialise:base,
+               serialise:containers,
+               cborg:base,
+               haddock-library:base
+
 if arch(wasm32)
   tests: False
 

pandoc.cabal

@@ -11,7 +11,7 @@ bug-reports:     https://github.com/jgm/pandoc/issues
 stability:       alpha
 homepage:        https://pandoc.org
 category:        Text
-tested-with:     GHC == 9.6.7, GHC == 9.8.4, GHC == 9.10.3, GHC == 9.12.2
+tested-with:     GHC == 9.6.7, GHC == 9.8.4, GHC == 9.10.3, GHC == 9.12.2, GHC == 9.14.1
 synopsis:        Conversion between markup formats
 description:     Pandoc is a Haskell library for converting from one markup
                  format to another.  The formats it can handle include