bump external API version number (#5004)

This is a semi-cowardly approach. Rather than actually implementing the
non-integer we
[determined](https://rfd.shared.oxide.computer/rfd/0299#_determinations),
this moves us from 0.0.1 to 0.0.6 (6 for release 6). This is to dry run
the oxide.rs [versioned release
process](https://github.com/oxidecomputer/oxide.rs?tab=readme-ov-file#determine-the-version-number).

nexus/src/lib.rs

@@ -47,7 +47,7 @@ extern crate slog;
 /// to stdout.
 pub fn run_openapi_external() -> Result<(), String> {
     external_api()
-        .openapi("Oxide Region API", "0.0.1")
+        .openapi("Oxide Region API", "0.0.6")
         .description("API for interacting with the Oxide control plane")
         .contact_url("https://oxide.computer")
         .contact_email("[email protected]")

nexus/tests/integration_tests/commands.rs

@@ -109,7 +109,7 @@ fn test_nexus_openapi() {
         .expect("stdout was not valid OpenAPI");
     assert_eq!(spec.openapi, "3.0.3");
     assert_eq!(spec.info.title, "Oxide Region API");
-    assert_eq!(spec.info.version, "0.0.1");
+    assert_eq!(spec.info.version, "0.0.6");
 
     // Spot check a couple of items.
     assert!(!spec.paths.paths.is_empty());

openapi/nexus.json

@@ -7,7 +7,7 @@
       "url": "https://oxide.computer",
       "email": "[email protected]"
     },
-    "version": "0.0.1"
+    "version": "0.0.6"
   },
   "paths": {
     "/device/auth": {