Add CI workflow that ensures released pkg builds with latest GHC

Author: adithyaov

.github/workflows/haskell.yml

@@ -95,6 +95,16 @@ jobs:
             cabal_project: cabal.project.ghc-head
             disable_sdist_build: "y"
             ignore_error: true
+          # This CI makes sure that the packages on hackage are compatible with
+          # the latest GHC release.
+          - name: 9.12.1-hackage-sdist
+            ghc_version: 9.12.1
+            runner: ubuntu-latest
+            build: cabal
+            cabal_build_options: "--flag limit-build-mem"
+            cabal_version: 3.12.1.0
+            ignore_error: false
+            subdir: dummy-package
           - name: 9.12.1
             ghc_version: 9.12.1
             runner: ubuntu-latest

.packcheck.ignore

@@ -35,3 +35,5 @@ targets/default.nix
 targets/cabal.project
 test/test-runner/default.nix
 test/test-runner/cabal.project
+dummy-package/dummy-package.cabal
+dummy-package/MyLib.hs

dummy-package/MyLib.hs

@@ -0,0 +1,4 @@
+module MyLib (someFunc) where
+
+someFunc :: IO ()
+someFunc = putStrLn "someFunc"

dummy-package/dummy-package.cabal

@@ -0,0 +1,17 @@
+cabal-version:      3.0
+name:               dummy-package
+version:            0.1.0.0
+license:            BSD-3-Clause
+build-type:         Simple
+
+common warnings
+    ghc-options: -Wall
+
+library
+    import:           warnings
+    exposed-modules:  MyLib
+    build-depends:    base
+                    , streamly
+                    , streamly-core
+    hs-source-dirs:   .
+    default-language: Haskell2010