🦊 Exit status 1 on cancelled selection (#20)

When making no selection, i.e. cancelling during the selection process
the program will return status code 1, whereas before it would carry the
same return code as when making an emoji selection.

Fixes #20.

test/bemoji_cmds.bats

@@ -64,6 +64,11 @@ typing result"
     assert_output "my clipping"
 }
 
+@test "Returns status code 1 on picker status code 1" {
+    BEMOJI_PICKER_CMD="return 1" run bemoji -e 3>&-
+    assert_failure 1
+}
+
 @test "Prints output with newline by default" {
     bats_require_minimum_version 1.5.0
     BEMOJI_PICKER_CMD="echo heart" run --keep-empty-lines -- bemoji -e