Update changelog

Author: taiki-e

CHANGELOG.md

@@ -12,6 +12,16 @@ Note: In this file, do not use the hard wrap in the middle of a sentence for com
 
 ## [Unreleased]
 
+- Update to stabilized [PowerPC64](https://github.com/rust-lang/rust/pull/147996) inline assembly. ([1bbeaf0a](https://github.com/taiki-e/portable-atomic/commit/1bbeaf0a192eedf706d61b7d4f47121671a82622))
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+- Work around [rustc_codegen_gcc bugs on x86_64](https://github.com/rust-lang/rustc_codegen_gcc/issues/821#issuecomment-3793567607). ([ae4c501](https://github.com/taiki-e/portable-atomic/commit/ae4c501aec84a3537fe35ec57ceae94b3a05ade0))
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+- Optimize x86_64 128-bit atomics. ([a9d61eb](https://github.com/taiki-e/portable-atomic/commit/a9d61ebf8d7f466286a71a17f7d9063fcf07fce0), [90a17ca4](https://github.com/taiki-e/portable-atomic/commit/90a17ca40a8ff433d767c3b56264fb02ccdd71e1))
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+- Improve compile-time detection of RISC-V target features. ([535fced](https://github.com/taiki-e/portable-atomic/commit/535fced071ed095ee4d35b440ba55a0e2f533d80))
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+- Enable [release immutability](https://docs.github.com/en/code-security/supply-chain-security/understanding-your-software-supply-chain/immutable-releases).
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 ## [1.13.0] - 2025-12-27
 
 - Add `unsafe-assume-privileged` feature / `portable_atomic_unsafe_assume_privileged` cfg for safer lock-based fallback on multi-core privileged environments. ([b084ee1](https://github.com/taiki-e/portable-atomic/commit/b084ee1b6cba3e9d7158a6c9e5450e1fc8bbde36))