fix(smithy-client): use uppercase for percent encodings (#2500)

Author: trivikr

Diff for: packages/smithy-client/src/extended-encode-uri-component.spec.ts

@@ -0,0 +1,20 @@
+import { extendedEncodeURIComponent } from "./extended-encode-uri-component";
+
+describe(extendedEncodeURIComponent.name, () => {
+  const encodedValues: [string, string][] = [
+    ["!", "%21"],
+    ["'", "%27"],
+    ["(", "%28"],
+    [")", "%29"],
+    ["*", "%2A"],
+  ];
+
+  const verify = (table: [string, string][]) => {
+    it.each(table)(`encodes %s as %s`, (input, output) => {
+      expect(extendedEncodeURIComponent(input)).toStrictEqual(output);
+    });
+  };
+
+  verify(encodedValues);
+  verify([encodedValues.reduce((acc, [input, output]) => [acc[0].concat(input), acc[1].concat(output)], ["", ""])]);
+});

Diff for: packages/smithy-client/src/extended-encode-uri-component.ts

@@ -4,6 +4,6 @@
  */
 export function extendedEncodeURIComponent(str: string): string {
   return encodeURIComponent(str).replace(/[!'()*]/g, function (c) {
-    return "%" + c.charCodeAt(0).toString(16);
+    return "%" + c.charCodeAt(0).toString(16).toUpperCase();
   });
 }