Update upload input values and logic (#1598)

- The `upload` input to the `analyze` Action now accepts the following values:
    - `always` is the default value, which uploads the SARIF file to Code Scanning for successful and failed runs.
    - `failure-only` is recommended for customers post-processing the SARIF file before uploading it to Code Scanning. This option uploads debugging information to Code Scanning for failed runs to improve the debugging experience.
    - `never` avoids uploading the SARIF file to Code Scanning even if the code scanning run fails. This is not recommended for external users since it complicates debugging.
    - The legacy `true` and `false` options will be interpreted as `always` and `failure-only` respectively.

---------

Co-authored-by: Henry Mercer <henry.mercer@me.com>

src/workflow.ts

@@ -426,22 +426,20 @@ export function getCategoryInputOrThrow(
  *
  * Typically you'll want to wrap this function in a try/catch block and handle the error.
  *
- * @returns the upload input
+ * @returns the user input to upload, or undefined if input was unspecified
  * @throws an error if the upload input could not be determined
  */
 export function getUploadInputOrThrow(
   workflow: Workflow,
   jobName: string,
   matrixVars: { [key: string]: string } | undefined
-): string {
-  return (
-    getInputOrThrow(
-      workflow,
-      jobName,
-      getAnalyzeActionName(),
-      "upload",
-      matrixVars
-    ) || "true" // if unspecified, upload defaults to true
+): string | undefined {
+  return getInputOrThrow(
+    workflow,
+    jobName,
+    getAnalyzeActionName(),
+    "upload",
+    matrixVars
   );
 }