try to run check-sdist on the right ghcs

(cherry picked from commit 6a2b5a7)

.github/workflows/check-sdist.yml

@@ -37,23 +37,17 @@ jobs:
   # No caching, since the point is to verify they can be installed "from scratch"
   # Don't run on master or a PR targeting master, because there's never an installable Cabal
   dogfood-sdists:
-    name: Dogfood sdist on ${{ matrix.os }} ghc-${{ matrix.ghc }}
+    name: Dogfood sdist on ghc-${{ matrix.ghc }}
     if: github.ref != 'refs/heads/master' && github.base_ref != 'master'
-    runs-on: ${{ matrix.os }}
+    runs-on: ubuntu-latest
     strategy:
       matrix:
-        os: [ubuntu-latest]
         # this should be kept up to date with the list in validate.yml, but should be the
         # *first* compiler release so we validate against what is hopefully the first
         # release of a corresponding Cabal and friends. it can also be short since it's
         # highly unlikely that we are releasing really old branches.
         ghc:
-          [
-            "9.10.1",
-            "9.8.1",
-            "9.6.1",
-            "9.4.1",
-          ]
+          ["9.10.1", "9.8.1", "9.6.1"]
 
     steps:
 
@@ -78,8 +72,9 @@ jobs:
           sdist="$(ls dist-newstyle/sdist/cabal-install-*.tar.gz | sed -n '\,^dist-newstyle/sdist/cabal-install-[0-9.]*\.tar\.gz$,{;p;q;}')"
           # extract the cabal-install major version
           ver="$(echo "$sdist" | sed -n 's,^dist-newstyle/sdist/cabal-install-\([0-9][0-9]*\.[0-9][0-9]*\)\.[0-9.]*$,\1,p')"
+          echo "$ver"
           # dunno if this will ever be extended to freebsd, but grep -q is a gnu-ism
-          if ghc-pkg --global --simple-output list Cabal | grep "^Cabal-$cbl\\." >/dev/null; then
+          if ghc-pkg --global --simple-output list Cabal | grep "^Cabal-$ver\\." >/dev/null; then
             # sigh, someone broke installing from tarballs
             rm -rf cabal*.project Cabal Cabal-syntax cabal-install-solver cabal-install
             tar xfz "$sdist"