chore: pin lychee to patch version in mise (#33)

Pins lychee to a concrete patch version (0.24.2) instead of "latest", and upgrades the existing mise.lock to lockfile format v3.

Reviewed-on: #33
Co-authored-by: Max Mehl <mail@mehl.mx>

mise.toml

@@ -1,6 +1,6 @@
 [tools]
 hugo-extended = "0.165.0"
-lychee = "latest"
+lychee = "0.24.2"
 
 [vars]
 build_dir = "public"