Relax build strictness in lower GHCs

Author: adithyaov

.github/workflows/packcheck.yml

@@ -123,15 +123,13 @@ jobs:
             ghc_version: 8.8.4
             build: cabal
             cabal-version: 3.2
-            cabal_project: cabal.project.Werror
             disable_docs: y
 
           - name: 8.6.5
             runner: ubuntu-latest
             ghc_version: 8.6.5
             build: cabal
             cabal-version: 3.2
-            cabal_project: cabal.project.Werror
             disable_docs: y
 
     steps: