Bump version to 0.2.0

The first version with a genuinely usable feature set (mount/run,
volumes, networking, exec/kill/daemonize, and compose orchestration) --
picking a round number for it rather than continuing to increment from
the original placeholder 0.0.1.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz

meson.build

@@ -1,5 +1,5 @@
 project('slocker-lite', 'cpp',
-        version : '0.0.1',
+        version : '0.2.0',
         default_options : ['warning_level=3', 'cpp_std=c++20'])
 
 fmt_dep = dependency('fmt')