Add entry to unreleased section of change log

Author: mpilgrem

CHANGELOG.md

@@ -1,5 +1,7 @@
 ## Unreleased
   - Add support for `extra-files` (see #603)
+  - Add new section: `foreign-libraries`, for Cabal 2.0's `foreign-library`
+    stanzas (see #518)
 
 ## Changes in 0.38.0
   - Generate `build-tool-depends` instead of `build-tools` starting with

README.md

@@ -151,7 +151,7 @@ library:
 | `custom-setup` | · | | See [Custom setup](#custom-setup) | | |
 | `flags`  | `flag <name>` | | Map from flag name to flag (see [Flags](#flags)) | | |
 | `library` | · | | See [Library fields](#library-fields) | | |
-| `foreign-libraries` | `foreign-library <name>` | | Map from foreign library name to a dict of [Foreign library fields](#foreign-library-fields) and global top-level fields. | | `0.39.0` |
+| `foreign-libraries` | `foreign-library <name>` | | Map from foreign library name to a dict of [Foreign library fields](#foreign-library-fields) and global top-level fields. | | UNRELEASED |
 | `internal-libraries` | `library <name>` | | Map from internal library name to a dict of [library fields](#library-fields) and global top-level fields. | | `0.21.0` |
 | `executables` | `executable <name>` | | Map from executable name to executable (see [Executable fields](#executable-fields)) | | |
 | `executable` | `executable <package-name>` | | Shortcut for `executables: { package-name: ... }` | | `0.18.0` |