feat(IamAssumeAuthenticator): add new authentication type for iam assume

This commit introduces the new IamAssumeAuthenticator which will fetch an IAM
access token using the IAM getToken operation's "assume" grant type. The
resulting access token allows the application to assume the identity of a
trusted profile, similar to the "sudo" feature of Linux.

Signed-off-by: Dustin Popp <dustinpopp@ibm.com>

.secrets.baseline

@@ -3,7 +3,7 @@
     "files": "package-lock.json|^.secrets.baseline$",
     "lines": null
   },
-  "generated_at": "2024-08-29T14:54:57Z",
+  "generated_at": "2024-10-04T17:22:24Z",
   "plugins_used": [
     {
       "name": "AWSKeyDetector"
@@ -70,23 +70,55 @@
         "hashed_secret": "91dfd9ddb4198affc5c194cd8ce6d338fde470e2",
         "is_secret": false,
         "is_verified": false,
-        "line_number": 74,
+        "line_number": 75,
+        "type": "Secret Keyword",
+        "verified_result": null
+      },
+      {
+        "hashed_secret": "4f51cde3ac0a5504afa4bc06859b098366592c19",
+        "is_secret": false,
+        "is_verified": false,
+        "line_number": 236,
+        "type": "Secret Keyword",
+        "verified_result": null
+      },
+      {
+        "hashed_secret": "e87559ed7decb62d0733ae251ae58d42a55291d8",
+        "is_secret": false,
+        "is_verified": false,
+        "line_number": 238,
+        "type": "Secret Keyword",
+        "verified_result": null
+      },
+      {
+        "hashed_secret": "12f4a68ed3d0863e56497c9cdb1e2e4e91d5cb68",
+        "is_secret": false,
+        "is_verified": false,
+        "line_number": 302,
+        "type": "Secret Keyword",
+        "verified_result": null
+      },
+      {
+        "hashed_secret": "c837b75d7cd93ef9c2243ca28d6e5156259fd253",
+        "is_secret": false,
+        "is_verified": false,
+        "line_number": 306,
         "type": "Secret Keyword",
         "verified_result": null
       },
       {
         "hashed_secret": "98635b2eaa2379f28cd6d72a38299f286b81b459",
         "is_secret": false,
         "is_verified": false,
-        "line_number": 433,
+        "line_number": 558,
         "type": "Secret Keyword",
         "verified_result": null
       },
       {
         "hashed_secret": "47fcf185ee7e15fe05cae31fbe9e4ebe4a06a40d",
         "is_secret": false,
         "is_verified": false,
-        "line_number": 543,
+        "line_number": 668,
         "type": "Secret Keyword",
         "verified_result": null
       }
@@ -96,7 +128,7 @@
         "hashed_secret": "bc2f74c22f98f7b6ffbc2f67453dbfa99bce9a32",
         "is_secret": false,
         "is_verified": false,
-        "line_number": 207,
+        "line_number": 214,
         "type": "Secret Keyword",
         "verified_result": null
       }
@@ -116,7 +148,7 @@
         "hashed_secret": "fdee05598fdd57ff8e9ae29e92c25a04f2c52fa6",
         "is_secret": false,
         "is_verified": false,
-        "line_number": 39,
+        "line_number": 41,
         "type": "Secret Keyword",
         "verified_result": null
       }
@@ -239,6 +271,16 @@
         "verified_result": null
       }
     ],
+    "auth/token-managers/iam-assume-token-manager.ts": [
+      {
+        "hashed_secret": "faed0c503983c5ab06e19630096d39ebfafef86a",
+        "is_secret": false,
+        "is_verified": false,
+        "line_number": 108,
+        "type": "Secret Keyword",
+        "verified_result": null
+      }
+    ],
     "auth/token-managers/iam-request-based-token-manager.ts": [
       {
         "hashed_secret": "f84f793e0af9ade37c8b927bc5091e98f35bf821",
@@ -314,7 +356,7 @@
         "hashed_secret": "6947818ac409551f11fbaa78f0ea6391960aa5b8",
         "is_secret": false,
         "is_verified": false,
-        "line_number": 50,
+        "line_number": 51,
         "type": "Secret Keyword",
         "verified_result": null
       }
@@ -334,7 +376,7 @@
         "hashed_secret": "45c43fe97e3a06ab078b0eeff6fbe622cc417a25",
         "is_secret": false,
         "is_verified": false,
-        "line_number": 266,
+        "line_number": 286,
         "type": "Secret Keyword",
         "verified_result": null
       }
@@ -455,6 +497,42 @@
         "verified_result": null
       }
     ],
+    "test/unit/iam-assume-authenticator.test.js": [
+      {
+        "hashed_secret": "9cea46b39bd44a1ef9f3e71bfe9e45c24d3300f6",
+        "is_secret": false,
+        "is_verified": false,
+        "line_number": 33,
+        "type": "Secret Keyword",
+        "verified_result": null
+      },
+      {
+        "hashed_secret": "5c5a15a8b0b3e154d77746945e563ba40100681b",
+        "is_secret": false,
+        "is_verified": false,
+        "line_number": 37,
+        "type": "Secret Keyword",
+        "verified_result": null
+      }
+    ],
+    "test/unit/iam-assume-token-manager.test.js": [
+      {
+        "hashed_secret": "a0da30f332dd7b7a26d1c0b4da5437fcd90bf49b",
+        "is_secret": false,
+        "is_verified": false,
+        "line_number": 34,
+        "type": "Secret Keyword",
+        "verified_result": null
+      },
+      {
+        "hashed_secret": "9cea46b39bd44a1ef9f3e71bfe9e45c24d3300f6",
+        "is_secret": false,
+        "is_verified": false,
+        "line_number": 148,
+        "type": "Secret Keyword",
+        "verified_result": null
+      }
+    ],
     "test/unit/iam-authenticator.test.js": [
       {
         "hashed_secret": "257368587362aab7f1180b4a5fe550ec26053e05",
@@ -582,7 +660,7 @@
       }
     ]
   },
-  "version": "0.13.1+ibm.62.dss",
+  "version": "0.13.1+ibm.56.dss",
   "word_list": {
     "file": null,
     "hash": null