release: bump 0.8.5 -> 0.8.6 (#260)

Version bump `0.8.5` → `0.8.6`.

### Changed
- Package registry metadata for better discoverability (#259):
  - R (R-universe): R-universe URL + `X-schema.org-keywords` in `DESCRIPTION`, package logo at `bindings/r/man/figures/logo.png`.
  - Python (PyPI): `Documentation` project URL.
  - C# (NuGet): package icon via `PackageIcon`.

Ships the metadata so the next PyPI/NuGet publish carries the new fields (R-universe rebuilds from main independently). Bump touches the manual release touchpoints only; docs/webpage version strings are left to `sync-about.yml` on the tag.

examples/node/package-lock.json

@@ -17,7 +17,7 @@
     },
     "../../bindings/node": {
       "name": "wickra",
-      "version": "0.8.5",
+      "version": "0.8.6",
       "license": "MIT OR Apache-2.0",
       "devDependencies": {
         "@napi-rs/cli": "^2.18.0"
@@ -26,12 +26,12 @@
         "node": ">= 18"
       },
       "optionalDependencies": {
-        "wickra-darwin-arm64": "0.8.5",
-        "wickra-darwin-x64": "0.8.5",
-        "wickra-linux-arm64-gnu": "0.8.5",
-        "wickra-linux-x64-gnu": "0.8.5",
-        "wickra-win32-arm64-msvc": "0.8.5",
-        "wickra-win32-x64-msvc": "0.8.5"
+        "wickra-darwin-arm64": "0.8.6",
+        "wickra-darwin-x64": "0.8.6",
+        "wickra-linux-arm64-gnu": "0.8.6",
+        "wickra-linux-x64-gnu": "0.8.6",
+        "wickra-win32-arm64-msvc": "0.8.6",
+        "wickra-win32-x64-msvc": "0.8.6"
       }
     },
     "node_modules/wickra": {