Update rustfmt config to edition 2018

cmichi · cmichi · commit f9f4b78a2d42 · 2021-10-21T20:28:35.000+02:00
diff --git a/.rustfmt.toml b/.rustfmt.toml
@@ -43,7 +43,7 @@ trailing_comma = "Vertical"
 match_block_trailing_comma = false
 blank_lines_upper_bound = 1
 blank_lines_lower_bound = 0
-edition = "2018" # changed
+edition = "2021" # changed
 version = "One"
 merge_derives = true
 use_try_shorthand = true # changed
