Make procuctId to URL translation work again (#50)

Author: Vampire

.github/workflows/test.main.kts

@@ -108,8 +108,7 @@ val ubuntu1604 = mapOf(
 
 val distributions = listOf(
     debian,
-    // disable testing on Alpine for the time being due to https://github.com/Vampire/setup-wsl/issues/50
-    //alpine,
+    alpine,
     kali,
     openSuseLeap15_2,
     ubuntu2204,

src/main/kotlin/net/kautler/github/action/setup_wsl/Distribution.kt

@@ -63,7 +63,8 @@ sealed class Distribution(
                 requestUrl = "https://store.rg-adguard.net/api/GetFiles",
                 data = "type=ProductId&url=$productId",
                 additionalHeaders = recordOf(
-                    "Content-Type" to "application/x-www-form-urlencoded"
+                    "Content-Type" to "application/x-www-form-urlencoded",
+                    "User-Agent" to "Setup WSL GitHub Action"
                 )
             ).await()
 
@@ -73,7 +74,8 @@ sealed class Distribution(
                         requestUrl = "https://echo.free.beeceptor.com/api/GetFiles",
                         data = "type=ProductId&url=$productId",
                         additionalHeaders = recordOf(
-                            "Content-Type" to "application/x-www-form-urlencoded"
+                            "Content-Type" to "application/x-www-form-urlencoded",
+                            "User-Agent" to "Setup WSL GitHub Action"
                         )
                     ).await()
                     if (echoResponse.message.statusCode == 200) {