deps: bump encoding_rs to 0.8.16

This brings in an updated `encoding_rs` crate that uses `packed_simd`,
which compiles on the latest nightly. Compilation times do appear to be
impacted significantly though.

Fixes #1175 (again)

CHANGELOG.md

@@ -14,9 +14,8 @@ TODO.
 * The `avx-accel` feature of ripgrep has been removed since it is no longer
   necessary. All uses of AVX in ripgrep are now enabled automatically via
   runtime CPU feature detection. The `simd-accel` feature does remain
-  available, however, it is broken in the latest nightly release of Rust.
-  See [#1175](https://github.com/BurntSushi/ripgrep/issues/1175) for more
-  info.
+  available, however, it does increase compilation times substantially at the
+  moment.
 
 Feature enhancements:
 

README.md

@@ -375,19 +375,15 @@ $ ./target/release/rg --version
 If you have a Rust nightly compiler and a recent Intel CPU, then you can enable
 additional optional SIMD acceleration like so:
 
-**WARNING**: Building with the `simd-accel` feature on the latest Rust nightly
-does not work because the [`encoding_rs`](https://crates.io/crates/encoding_rs)
-crate hasn't yet migrated to the new SIMD infrastructure, and the old SIMD
-infrastructure no longer works on the latest nightly version of Rust.
-
 ```
 RUSTFLAGS="-C target-cpu=native" cargo build --release --features 'simd-accel'
 ```
 
 The `simd-accel` feature enables SIMD support in certain ripgrep dependencies
 (responsible for transcoding). They are not necessary to get SIMD optimizations
 for search; those are enabled automatically. Hopefully, some day, the
-`simd-accel` feature will similarly become unnecessary.
+`simd-accel` feature will similarly become unnecessary. **WARNING:** Currently,
+enabling this option can increase compilation times dramatically.
 
 Finally, optional PCRE2 support can be built with ripgrep by enabling the
 `pcre2` feature: