Add 5919 and 6410 (cabal install improvements) mentions to changelog

Author: phadej

cabal-install/changelog

@@ -7,6 +7,11 @@
 	  ([#6385](https://github.com/haskell/cabal/pull/6385))
 	* Update `setupMinCabalVersionConstraint` for GHC-8.8
 	  ([#6217](https://github.com/haskell/cabal/pull/6217))
+	* Implement `cabal install --ignore-project`
+	  ([#5919](https://github.com/haskell/cabal/issues/5919))
+	* `cabal install executable` solver isn't affected by default
+	  environment contents
+	  ([#6410](https://github.com/haskell/cabal/issues/6410))
 	* Use `lukko` for file locking
 	  ([#6345](https://github.com/haskell/cabal/pull/6345))
 	* Use `hackage-security-0.6`