Add changelog entry

Author: Kleidukos

changelog.d/pr-8794

@@ -0,0 +1,10 @@
+synopsis: Disallow GHC <8.0 for 
+packages: Cabal Cabal-syntax cabal-install-solver
+prs: #8794
+issues: #8715 #7531
+
+description: {
+
+Disallow GHC <8.0 by restricting the version of base that can be used to at least 4.9
+
+}