Update backwards compatability section of CONTRIBUTING.md

Author: mpilgrem

CONTRIBUTING.md

@@ -341,7 +341,7 @@ compatibility with a range of versions of GHC that a library package (such as
 Stack aims to depend on well-known packages. The specific versions on which it
 depends at any time are specified by `package.yaml` and `stack.yaml`. It does
 not aim to be compatible with more than one version of the `Cabal` package at
-any time. At the time of writing (May 2024) the package versions are primarily
+any time. At the time of writing (July 2024) the package versions are primarily
 ones in Stackage snapshot LTS Haskell 22.28 (for GHC 9.6.6), together with
 extra-deps to depend on the latest version of `hpack`, `pantry` and `tar`.