circleci: fix nightly release

Also delete unused variable in release/default.nix

.circleci/config.yml

@@ -127,6 +127,14 @@ jobs:
           command: |
             curl -L https://nixos.org/nix/install | sh
             echo "source $HOME/.nix-profile/etc/profile.d/nix.sh" >> $BASH_ENV
+      - run:
+          name: Change postgrest.cabal if nightly
+          command: |
+            if test "$CIRCLE_TAG" = "nightly"
+            then
+              cabal_nightly_version=$(git show -s --format='%cd' --date='format:%Y%m%d')
+              sed -i "s/^version:.*/version:$cabal_nightly_version/" postgrest.cabal
+            fi
       - run:
           name: Install and use the Cachix binary cache
           command: |

nix/release/default.nix

@@ -9,9 +9,6 @@
 , writeShellScriptBin
 }:
 let
-  # Version from the postgrest.cabal file (gotten with callCabal2nix).
-  version = postgrest.version;
-
   # Script for publishing a new release on GitHub.
   github =
     writeShellScriptBin "postgrest-release-github"