allow including extra info in --version output

Signed-off-by: strawberry <strawberry@puppygock.gay>

flake.nix

@@ -73,6 +73,7 @@
       ];
 
       env = pkgs: {
+        CONDUIT_VERSION_EXTRA = self.shortRev or self.dirtyShortRev;
         ROCKSDB_INCLUDE_DIR = "${rocksdb' pkgs}/include";
         ROCKSDB_LIB_DIR = "${rocksdb' pkgs}/lib";
       }