release: bump workspace version 0.1.1 -> 0.2.0 (#292)

Prepares the v0.2.0 release. `cargo update --workspace` rewrites only the
31 workspace-member version entries in Cargo.lock; no external deps move.
`q2 --version` reports "q2 (quarto 2) 0.2.0".

Strand: bd-56hbab5q

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 = "0.1.1"
+version = "0.2.0"
 authors = ["Posit Software, PBC"]
 homepage = "https://github.com/posit-dev/quarto-markdown-syntax"
 keywords = ["parser"]