Support various YAML extensions

Author: krzema12

composeApp/src/commonMain/kotlin/ManifestFetching.kt

@@ -1,11 +1,20 @@
 import com.charleskorn.kaml.Yaml
 import io.ktor.client.call.body
 import io.ktor.client.request.get
+import io.ktor.http.HttpStatusCode
 import kotlinx.serialization.decodeFromString
 
 suspend fun fetchManifest(actionCoords: String): Metadata? {
-    val yaml = client.get(urlString = "https://raw.githubusercontent.com/${actionCoords.replace("@", "/")}/action.yml")
-        .body<String>()
+    val yaml = listOf("yml", "yaml").firstNotNullOfOrNull { extension ->
+        val response = client
+            .get(urlString = "https://raw.githubusercontent.com/${actionCoords.replace("@", "/")}/action.$extension")
+        if (response.status == HttpStatusCode.OK) {
+            response.body<String>()
+        } else {
+            null
+        }
+    } ?: return null
+
     return try {
         myYaml.decodeFromString<Metadata>(yaml)
     } catch (e: Exception) {