Recover the complicated situation after my bad merge

I made a mistake merge.  Reverting it in c778945806b undid the state
on master, but now I realize it crippled the git merge mechanism.
As the merge contained a mix of commits from `master..staging-next`
and other commits from `staging-next..staging`, it got the
`staging-next` branch into a state that was difficult to recover.

I reconstructed the "desired" state of staging-next tree by:
 - checking out the last commit of the problematic range: 4effe769e2b
 - `git rebase -i --preserve-merges a8a018ddc0` - dropping the mistaken
   merge commit and its revert from that range (while keeping
   reapplication from 4effe769e2)
 - merging the last unaffected staging-next commit (803ca85c209)
 - fortunately no other commits have been pushed to staging-next yet
 - applying a diff on staging-next to get it into that state

1 files changed, 3 insertions, 3 deletions

diff --git a/pkgs/data/misc/tzdata/default.nix b/pkgs/data/misc/tzdata/default.nix
index 367ee06390cd..dc80580ff5ec 100644
--- a/pkgs/data/misc/tzdata/default.nix
+++ b/pkgs/data/misc/tzdata/default.nix
@@ -2,16 +2,16 @@
 
 stdenv.mkDerivation rec {
   pname = "tzdata";
-  version = "2019c";
+  version = "2020c";
 
   srcs =
     [ (fetchurl {
         url = "https://data.iana.org/time-zones/releases/tzdata${version}.tar.gz";
-        sha256 = "0z7w1yv37cfk8yhix2cillam091vgp1j4g8fv84261q9mdnq1ivr";
+        sha256 = "1nab36g5ibs88wg2mzpzygi1wh5gh2al1qjvbk8sb90sbw8ar43q";
       })
       (fetchurl {
         url = "https://data.iana.org/time-zones/releases/tzcode${version}.tar.gz";
-        sha256 = "1m3y2rnf1nggxxhxplab5zdd5whvar3ijyrv7lifvm82irkd7szn";
+        sha256 = "1r5zrk1k3jhhilkhrx82fd19rvysji8jk05gq5v0rndmyx07zacs";
       })
     ];