fix: Pin karma-credential-loader to 3.38.0 (#795)

Author: lavaleri

modules/integration-browser/package.json

@@ -20,7 +20,7 @@
     "@aws-crypto/client-browser": "file:../client-browser",
     "@aws-crypto/integration-vectors": "file:../integration-vectors",
     "@aws-sdk/credential-provider-node": "^3.11.0",
-    "@aws-sdk/karma-credential-loader": "^3.11.0",
+    "@aws-sdk/karma-credential-loader": "3.38.0",
     "@aws-sdk/util-base64-browser": "^3.10.0",
     "@aws-sdk/util-utf8-browser": "3.23.0",
     "@trust/keyto": "^1.0.1",