Stop pinning the package version in the User-Agent test

The assertion compared the resolved header against the literal
"skylink-api-node/0.1.0", so the suite failed on any version bump — it would
have blocked the very first release after 0.1.0, in the release workflow, with
an error that looks nothing like its cause.

The header is now compared against the USER_AGENT constant, and the shape is
asserted separately, so a missing or malformed version is still caught while a
bump is not.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: AlexLovser

tests/client.test.ts

@@ -82,9 +82,11 @@ describe("resolveConfig", () => {
 
   it("sends the node User-Agent", () => {
     expect(USER_AGENT).toBe(`skylink-api-node/${VERSION}`);
-    expect(resolveConfig({ apiKey: "k" }).defaultHeaders["User-Agent"]).toBe(
-      "skylink-api-node/0.1.0",
-    );
+    expect(resolveConfig({ apiKey: "k" }).defaultHeaders["User-Agent"]).toBe(USER_AGENT);
+    // Shape, not a pinned number: asserting the literal version here made every
+    // release fail the suite, while a missing or malformed one is still caught.
+    expect(USER_AGENT.startsWith("skylink-api-node/")).toBe(true);
+    expect(VERSION.split(".")).toHaveLength(3);
   });
 
   it("falls back to RAPIDAPI_KEY on the default provider", () => {