release: bump 0.4.7 -> 0.5.0 (#159)

Version bump for the 0.5.0 release, which ships the relicense to MIT OR Apache-2.0.

Stacked on #158 (base branch `chore/relicense-mit-apache`) so this PR's diff is the bump only. After #158 merges to main, GitHub retargets this PR to main; merge it, then tag `v0.5.0` to publish.

## Changes
- Bump 0.4.7 -> 0.5.0 across the Cargo workspace, Python `pyproject.toml`, Node `package.json` + 6 platform manifests + 2 lockfiles, and `Cargo.lock`.
- CHANGELOG: cut the [0.5.0] section (the relicense) and add compare URLs.
- SECURITY.md: supported versions 0.4.x -> 0.5.x.

Minor (not patch) bump: a relicense is a significant change. No code changes.

NOTE: do not tag/release until you give the go (irreversible publish to crates.io/PyPI/npm). Suggested merge order: #158 -> this -> tag `v0.5.0` -> then the downstream PRs.

examples/node/package-lock.json

@@ -17,7 +17,7 @@
     },
     "../../bindings/node": {
       "name": "wickra",
-      "version": "0.4.7",
+      "version": "0.5.0",
       "license": "MIT OR Apache-2.0",
       "devDependencies": {
         "@napi-rs/cli": "^2.18.0"
@@ -26,12 +26,12 @@
         "node": ">= 18"
       },
       "optionalDependencies": {
-        "wickra-darwin-arm64": "0.4.7",
-        "wickra-darwin-x64": "0.4.7",
-        "wickra-linux-arm64-gnu": "0.4.7",
-        "wickra-linux-x64-gnu": "0.4.7",
-        "wickra-win32-arm64-msvc": "0.4.7",
-        "wickra-win32-x64-msvc": "0.4.7"
+        "wickra-darwin-arm64": "0.5.0",
+        "wickra-darwin-x64": "0.5.0",
+        "wickra-linux-arm64-gnu": "0.5.0",
+        "wickra-linux-x64-gnu": "0.5.0",
+        "wickra-win32-arm64-msvc": "0.5.0",
+        "wickra-win32-x64-msvc": "0.5.0"
       }
     },
     "node_modules/wickra": {