chore: upgrade toolchain to latest Elixir/Erlang/Rust

Bump .tool-versions to Elixir 1.20.0 / OTP 29.0 / Rust 1.93.1 and update
the CI test matrix to the three latest Elixir/OTP pairs.

OTP 29 also resolves the ssl key_usage_mismatch regression
(erlang/otp#9208, fixed by #9286) present in OTP 27.1.3-27.2, which
broke precompiled-NIF downloads from the GitHub release CDN during
`mix hex.publish`.

Remove an unused `require Logger` newly flagged by Elixir 1.20's
unused-require warning.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: fahchen

.github/workflows/ci.yml

@@ -87,15 +87,13 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - elixir: "1.18.3"
-            otp: "27.2"
+          - elixir: "1.20.0"
+            otp: "29.0"
             warnings_as_errors: true
-          - elixir: "1.17.3"
-            otp: "27.2"
-          - elixir: "1.17.3"
-            otp: "26.2"
-          - elixir: "1.16.3"
-            otp: "26.2"
+          - elixir: "1.19.5"
+            otp: "28.4"
+          - elixir: "1.18.4"
+            otp: "27.3.4.4"
     steps:
       - uses: actions/checkout@v5
 

.tool-versions

@@ -1,3 +1,3 @@
-elixir 1.18.3
-erlang 27.2
-rust 1.88.0
+elixir 1.20.0-otp-29
+erlang 29.0
+rust 1.93.1

lib/dprint_markdown_formatter.ex

@@ -92,8 +92,6 @@ defmodule DprintMarkdownFormatter do
 
   @behaviour Mix.Tasks.Format
 
-  require Logger
-
   alias DprintMarkdownFormatter.AstProcessor
   alias DprintMarkdownFormatter.Config
   alias DprintMarkdownFormatter.Error