CI: include GHC 9.12.1; add old GHCs back for macos-13

Author: andreasabel

.github/workflows/haskell.yml

@@ -11,10 +11,6 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        # Add more elements to this list to run multiple instances of the build in CI.  Increasing the
-        # number instances is a good way to trigger flaky build failures
-        n: [1]
-
         ghc:
         - "8.0.2"
         - "8.2.2"
@@ -26,10 +22,11 @@ jobs:
         - "9.2.8"
         - "9.4.8"
         - "9.6.6"
-        - "9.8.2"
+        - "9.8.4"
         - "9.10.1"
+        - "9.12.1"
         # FIXME: Add windows-latest back to CI once it is passing.
-        os: [ubuntu-latest, macos-latest]
+        os: [ubuntu-latest]
 
         # Action fails to install GHC < 8.10 on OSX with a generic error
         # messsage:
@@ -40,14 +37,20 @@ jobs:
         #
         #   Warning: Couldn't figure out LLVM version!
         #            Make sure you have installed LLVM between [9 and 13)
-        exclude:
-          - {ghc: "8.0.2", os: "macos-latest"}
-          - {ghc: "8.2.2", os: "macos-latest"}
-          - {ghc: "8.4.4", os: "macos-latest"}
-          - {ghc: "8.6.5", os: "macos-latest"}
-          - {ghc: "8.8.4", os: "macos-latest"}
-          - {ghc: "8.10.7", os: "macos-latest"}
-          - {ghc: "9.0.2", os: "macos-latest"}
+        include:
+          - {ghc: "8.0.2" , os: "macos-13"}
+          - {ghc: "8.2.2" , os: "macos-13"}
+          - {ghc: "8.4.4" , os: "macos-13"}
+          - {ghc: "8.6.5" , os: "macos-13"}
+          - {ghc: "8.8.4" , os: "macos-13"}
+          - {ghc: "8.10.7", os: "macos-13"}
+          - {ghc: "9.0.2" , os: "macos-13"}
+          - {ghc: "9.2.8" , os: "macos-latest"}
+          - {ghc: "9.4.8" , os: "macos-latest"}
+          - {ghc: "9.6.6" , os: "macos-latest"}
+          - {ghc: "9.8.4" , os: "macos-latest"}
+          - {ghc: "9.10.1", os: "macos-latest"}
+          - {ghc: "9.12.1", os: "macos-latest"}
     env:
       # OpenSSL is installed in a non-standard location in MacOS. See
       # https://github.com/actions/virtual-environments/blob/main/images/macos/macos-latest-Readme.md