chore(release): bump workspace version to 0.3.0 (bd-jbj5mtsr) (#299)

Bump [workspace.package].version 0.2.0 -> 0.3.0 and refresh Cargo.lock
workspace entries via `cargo update --workspace`. Preflight for the
Release workflow requires the git tag to equal the manifest version,
so this lands before tagging v0.3.0.

`cargo build --bin q2 --locked` succeeds; `q2 --version` prints
"q2 (quarto 2) 0.3.0".

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

Author: cscheid

Cargo.lock

@@ -23,7 +23,7 @@ exclude = [
 resolver = "2"
 
 [workspace.package]
-version = "0.2.0"
+version = "0.3.0"
 authors = ["Posit Software, PBC"]
 homepage = "https://github.com/posit-dev/quarto-markdown-syntax"
 keywords = ["parser"]