fix(ci): make release zips reproducible and bump version to 0.2.1

adm-zip stamps entries with file mtimes, i.e. the git checkout time on
CI, so two builds of the same commit differed byte-wise and tripped the
immutable no-overwrite guard on workflow re-runs. Pin every entry to the
commit date (SOURCE_DATE_EPOCH convention) instead.

0.2.0 was never published (no manifest entry, no GitHub release), but a
stale chrome-store zip from the first failed run occupies its immutable
slot; move the release to 0.2.1 rather than deleting the object.

package.json

@@ -2,7 +2,7 @@
   "name": "yakit-chrome-client",
   "description": "Yakit Browser Extension",
   "private": true,
-  "version": "0.2.0",
+  "version": "0.2.1",
   "type": "module",
   "packageManager": "[email protected]",
   "scripts": {