feat: support custom github url (#414)

Fix #344

action.yml

@@ -18,6 +18,10 @@ inputs:
   checksum:
     description: "The checksum of the uv version to install"
     required: false
+  server-url:
+    description: "The server url to use when downloading uv"
+    required: false
+    default: "https://github.com"
   github-token:
     description:
       "Used to increase the rate limit when retrieving versions and downloading uv."