release notes: update for rc1

RELEASE_NOTES.md

@@ -1,18 +1,25 @@
-we're proud to announce the first release candidate for the upcoming 2.4 series of darktable, 2.4.0rc0!
+we're proud to announce the second release candidate for the upcoming 2.4 series of darktable, 2.4.0rc1!
 
 as always, please don't use the autogenerated tarball provided by github, but only our tar.xz. the checksum is:
 
 ```
-$ sha256sum darktable-2.4.0rc0.tar.xz
-??? darktable-2.4.0rc0.tar.xz
-$ sha256sum darktable-2.4.0rc0.dmg
-??? darktable-2.4.0rc0.dmg
-$ sha256sum darktable-2.4.0rc0.exe
-??? darktable-2.4.0rc0.exe
+$ sha256sum darktable-2.4.0rc1.tar.xz
+??? darktable-2.4.0rc1.tar.xz
+$ sha256sum darktable-2.4.0rc1.dmg
+??? darktable-2.4.0rc1.dmg
+$ sha256sum darktable-2.4.0rc1.exe
+??? darktable-2.4.0rc1.exe
 ```
 
 #### Important note: to make sure that darktable can keep on supporting the raw file format for your camera, *please* read [this post](https://discuss.pixls.us/t/raw-samples-wanted/5420?u=lebedevri) on how/what raw samples you can contribute to ensure that we have the *full* raw sample set for your camera under CC0 license!
 
+## changes since rc0
+* noise profile for Nikon D4
+* Phase One IQ140 support
+* macintosh packaging fixes
+* lightroom import fixes
+
+
 and the changelog as compared to 2.2.0 can be found below. Some of the fixes might have been backported to the stable 2.2.x series already.
 - The maintainership of the RawSpeed library was transferred to the darktable project. The work on code cleanup, hardening, modernization, simplification and testing is ongoing.
 - Well over 2 thousand commits to darktable+rawspeed since 2.2.0