Allow multiple uploads in a single job

They must all have a unique category. The category will be
converted into an environment variable.

src/upload-lib.test.ts

@@ -175,3 +175,24 @@ test("populateRunAutomationDetails", (t) => {
   );
   t.deepEqual(modifiedSarif, expectedSarif);
 });
+
+test("validateUniqueCategory", (t) => {
+  t.notThrows(() => uploadLib.validateUniqueCategory(undefined));
+  t.throws(() => uploadLib.validateUniqueCategory(undefined));
+
+  t.notThrows(() => uploadLib.validateUniqueCategory("abc"));
+  t.throws(() => uploadLib.validateUniqueCategory("abc"));
+
+  t.notThrows(() => uploadLib.validateUniqueCategory("def"));
+  t.throws(() => uploadLib.validateUniqueCategory("def"));
+
+  // Our category sanitization is not perfect. Here are some examples
+  // of where we see false clashes
+  t.notThrows(() => uploadLib.validateUniqueCategory("abc/def"));
+  t.throws(() => uploadLib.validateUniqueCategory("abc@def"));
+  t.throws(() => uploadLib.validateUniqueCategory("abc_def"));
+  t.throws(() => uploadLib.validateUniqueCategory("abc def"));
+
+  // this one is fine
+  t.notThrows(() => uploadLib.validateUniqueCategory("abc_ def"));
+});