Prepare 1.20.0 release

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -1,3 +1,14 @@
+# (2026-06-02) Version 1.20.0
+
+- (**Internal Improvement**) Update [matrix-sdk](https://crates.io/crates/matrix-sdk) from 0.17 to 0.18 and [mxlink](https://crates.io/crates/mxlink) to 1.15.0.
+
+- (**Internal Improvement**) Update [tiktoken-rs](https://crates.io/crates/tiktoken-rs) to 0.12, backporting OpenAI [tiktoken](https://github.com/openai/tiktoken) 0.13.0 for better alignment with upstream tokenization behavior.
+
+- (**Internal Improvement**) Bump the pinned Rust toolchain from 1.95.0 to 1.96.0 (in `rust-toolchain.toml` and the Docker build images).
+
+- (**Internal Improvement**) Dependency updates.
+
+
 # (2026-05-27) Version 1.19.3
 
 - (**Internal Improvement**) Update [async-openai](https://crates.io/crates/async-openai) to 0.40.2, pulling in several upstream fixes (streaming HTTP error surfacing, default `ResponseTextParam.format` deserialization, etc.).

Cargo.lock

@@ -315,7 +315,7 @@ dependencies = [
 
 [[package]]
 name = "baibot"
-version = "1.19.3"
+version = "1.20.0"
 dependencies = [
  "anthropic",
  "anyhow",

Cargo.toml

@@ -7,7 +7,7 @@ license = "AGPL-3.0-or-later"
 readme = "README.md"
 keywords = ["matrix", "chat", "bot", "AI", "LLM"]
 include = ["/etc/assets/baibot-torso-768.png", "/src", "/README.md", "/CHANGELOG.md", "/LICENSE"]
-version = "1.19.3"
+version = "1.20.0"
 edition = "2024"
 
 [lib]