Add changelog for 0.31.1

chain-forgexcr45 · chain-forgexcr45 · commit eb6598c52651 · 2025-09-11T13:35:35.000+10:00
When we released the, albeit triival, point release we did not add a
changelog. Do so.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,3 +1,7 @@
+# 0.31.1 - 2025-06-23
+
+* Update deprecation notes with `since` instead of `TBD`.
+
 # 0.31.0 - 2025-04-21
 
 * Update `rand` to 0.9 [#788](https://github.com/rust-bitcoin/rust-secp256k1/pull/788)
