switch none deployment strategy to basic (#204)

* switch none deployment strategy to basic

* update readme

* update deployment strategy fallthrough logic

* comment fixed

* add disclaimer for basic strategy only supporting deploy action

src/strategyHelpers/deploymentHelper.ts

@@ -70,10 +70,7 @@ export async function deployManifests(
          return newFilePaths
       }
 
-      case undefined: {
-         core.warning('Deployment strategy is not recognized.')
-      }
-      default: {
+      case DeploymentStrategy.BASIC: {
          const trafficSplitMethod = parseTrafficSplitMethod(
             core.getInput('traffic-split-method', {required: true})
          )
@@ -94,6 +91,10 @@ export async function deployManifests(
 
          return files
       }
+
+      default: {
+         throw new Error('Deployment strategy is not recognized.')
+      }
    }
 }