Merge pull request #8532 from haskell/mergify/bp/3.8/pr-8531

Fix `bytestring` CI bug (backport #8531)

cabal-testsuite/PackageTests/postCheckoutCommand/cabal.negative.project

@@ -3,6 +3,7 @@ packages: .
 source-repository-package
     type: git
 -- A Sample repo to test post-checkout-command
-    location: https://github.com/haskell/bytestring 
+    location: https://github.com/haskell/bytestring
     post-checkout-command: false
+    tag: 0.10.9.0
 -- https://en.wikipedia.org/wiki/True_and_false_(commands)

cabal-testsuite/PackageTests/postCheckoutCommand/cabal.positive.project

@@ -5,4 +5,5 @@ source-repository-package
 -- A Sample repo to test post-checkout-command
     location: https://github.com/haskell/bytestring
     post-checkout-command: true
+    tag: 0.10.9.0
 -- https://en.wikipedia.org/wiki/True_and_false_(commands)