rawtherapee: 5.9 -> 5.10

New release from the 16th of February. See release notes on the official
website: https://www.rawtherapee.com/downloads/5.10/#news-relevant-to-package-maintainers

Noticeably:

- new exiv2 >= 0.24 dependency (nixpkgs currently distributes 0.28)
- avoid using Github releases as recommended in the release notes above

pkgs/applications/graphics/rawtherapee/default.nix

@@ -20,17 +20,21 @@
 , librsvg
 , libcanberra-gtk3
 , gtk-mac-integration
+, exiv2
 }:
 
 stdenv.mkDerivation rec {
   pname = "rawtherapee";
-  version = "5.9";
+  version = "5.10";
 
   src = fetchFromGitHub {
     owner = "Beep6581";
     repo = "RawTherapee";
     rev = version;
-    hash = "sha256-kdctfjss/DHEcaSDPXcmT20wXTwkI8moRX/i/5wT5Hg=";
+    hash = "sha256-rIwwKNm7l7oPEt95sHyRj4aF3mtnvM4KAu8oVaIMwyE=";
+    # The developpers ask not to use the tarball from Github releases, see
+    # https://www.rawtherapee.com/downloads/5.10/#news-relevant-to-package-maintainers
+    forceFetchGit = true;
   };
 
   postPatch = ''
@@ -61,6 +65,7 @@ stdenv.mkDerivation rec {
     libsigcxx
     lensfun
     librsvg
+    exiv2
   ] ++ lib.optionals stdenv.isLinux [
     libcanberra-gtk3
   ] ++ lib.optionals stdenv.isDarwin [