Merge #550: Update CHANGELOG for release of v0.25.0

01b1fbc Update CHANGELOG for release of v0.25.0 (Tobin C. Harding)

Pull request description:

  We just did a new release of `secp256k1-sys` needed for release of v0.25.0

  Update the CHANGELOG to include secp-sys version bump.

ACKs for top commit:
  apoelstra:
    ACK 01b1fbc

Tree-SHA512: 87ffc0f4ce468975b99ea3a0bbc97f8d0d048ecaee9982550bad13f564e0ea0093ce7dfdb7af0b5de8f14ff00eafd29bdb23dcf15ad52e93dc194459de0e15ab

Author: apoelstra

CHANGELOG.md

@@ -1,6 +1,7 @@
 # 0.25.0 - 2022-12-07
 
 * [Fix soundness issue with `preallocated_gen_new`](https://github.com/rust-bitcoin/rust-secp256k1/pull/548)
+* Update to `secp256k1-sys` [v0.7.0](https://github.com/rust-bitcoin/rust-secp256k1/pull/549)
 * Use type system to [improve safety](https://github.com/rust-bitcoin/rust-secp256k1/pull/483).
 * [Change secp256k1-sys symbol names to 0_6_1](https://github.com/rust-bitcoin/rust-secp256k1/pull/490).
 * [Introduce `rustfmt`](https://github.com/rust-bitcoin/rust-secp256k1/pull/499) to the codebase.