Add function for retrieving the "upload" input

Author: henrymercer

analyze/action.yml

@@ -12,6 +12,7 @@ inputs:
   upload:
     description: Upload the SARIF file to Code Scanning
     required: false
+    # If changing this, make sure to update workflow.ts accordingly.
     default: "true"
   cleanup-level:
     description: "Level of cleanup to perform on CodeQL databases at the end of the analyze step. This should either be 'none' to skip cleanup, or be a valid argument for the --mode flag of the CodeQL CLI command 'codeql database cleanup' as documented at https://codeql.github.com/docs/codeql-cli/manual/database-cleanup"