Add new option to specify behavior if no files found (#104)

* Add new option to specify behavior if no files found

src/constants.ts

@@ -1,8 +1,22 @@
 export enum Inputs {
   Name = 'name',
-  Path = 'path'
+  Path = 'path',
+  IfNoFilesFound = 'if-no-files-found'
 }
 
-export function getDefaultArtifactName(): string {
-  return 'artifact'
+export enum NoFileOptions {
+  /**
+   * Default. Output a warning but do not fail the action
+   */
+  warn = 'warn',
+
+  /**
+   * Fail the action with an error message
+   */
+  error = 'error',
+
+  /**
+   * Do not output any warnings or errors, the action does not fail
+   */
+  ignore = 'ignore'
 }